diff --git a/projects/GKCore/GDModel/GDMAddress.cs b/projects/GKCore/GDModel/GDMAddress.cs
index 470acfdad..892868b72 100644
--- a/projects/GKCore/GDModel/GDMAddress.cs
+++ b/projects/GKCore/GDModel/GDMAddress.cs
@@ -240,5 +240,25 @@ public void SetAddressArray(string[] value)
             fLines.Clear();
             fLines.AddRange(value);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddHash(fLines.GetHashCode());
+
+            hashCode.AddObj(fAddressLine1);
+            hashCode.AddObj(fAddressLine2);
+            hashCode.AddObj(fAddressLine3);
+            hashCode.AddObj(fAddressCity);
+            hashCode.AddObj(fAddressState);
+            hashCode.AddObj(fAddressPostalCode);
+            hashCode.AddObj(fAddressCountry);
+
+            ProcessHashes(ref hashCode, fPhoneList);
+            ProcessHashes(ref hashCode, fEmailList);
+            ProcessHashes(ref hashCode, fFaxList);
+            ProcessHashes(ref hashCode, fWWWList);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMAssociation.cs b/projects/GKCore/GDModel/GDMAssociation.cs
index 828b90ecd..359df411e 100644
--- a/projects/GKCore/GDModel/GDMAssociation.cs
+++ b/projects/GKCore/GDModel/GDMAssociation.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -102,5 +102,14 @@ public override void Assign(GDMTag source)
             fRelation = sourceObj.fRelation;
             if (sourceObj.fSourceCitations != null) AssignList(sourceObj.fSourceCitations, SourceCitations);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fRelation);
+
+            ProcessHashes(ref hashCode, fSourceCitations);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMChangeDate.cs b/projects/GKCore/GDModel/GDMChangeDate.cs
index b8e9613b7..74593606c 100644
--- a/projects/GKCore/GDModel/GDMChangeDate.cs
+++ b/projects/GKCore/GDModel/GDMChangeDate.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2019 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -71,5 +71,12 @@ public override bool IsEmpty()
         {
             return base.IsEmpty() && (fChangeDateTime.Equals(ZeroDateTime));
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fChangeDateTime);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMChildToFamilyLink.cs b/projects/GKCore/GDModel/GDMChildToFamilyLink.cs
index 3a201b796..c2184b310 100644
--- a/projects/GKCore/GDModel/GDMChildToFamilyLink.cs
+++ b/projects/GKCore/GDModel/GDMChildToFamilyLink.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -82,5 +82,13 @@ public override void Assign(GDMTag source)
             fChildLinkageStatus = srcCFL.fChildLinkageStatus;
             fPedigreeLinkageType = srcCFL.fPedigreeLinkageType;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fChildLinkageStatus);
+            hashCode.AddVal(fPedigreeLinkageType);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMCommunicationRecord.cs b/projects/GKCore/GDModel/GDMCommunicationRecord.cs
index 4ee71e799..97c958c52 100644
--- a/projects/GKCore/GDModel/GDMCommunicationRecord.cs
+++ b/projects/GKCore/GDModel/GDMCommunicationRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -155,5 +155,16 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             fCorresponder.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fCommName);
+            hashCode.AddVal(fCommunicationType);
+            hashCode.AddObj(fDate);
+            hashCode.AddVal(fCommDirection);
+            hashCode.AddObj(fCorresponder);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMCustomEvent.cs b/projects/GKCore/GDModel/GDMCustomEvent.cs
index 2e9a5c678..2caa7ebce 100644
--- a/projects/GKCore/GDModel/GDMCustomEvent.cs
+++ b/projects/GKCore/GDModel/GDMCustomEvent.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -296,5 +296,22 @@ public int GetChronologicalYear()
         {
             return Date.GetChronologicalYear();
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAddress);
+            hashCode.AddObj(fAgency);
+            hashCode.AddObj(fCause);
+            hashCode.AddObj(fClassification);
+            hashCode.AddObj(fDate);
+            hashCode.AddObj(fPlace);
+            hashCode.AddObj(fReligiousAffilation);
+            hashCode.AddVal(fRestriction);
+            ProcessHashes(ref hashCode, fNotes);
+            ProcessHashes(ref hashCode, fSourceCitations);
+            ProcessHashes(ref hashCode, fMultimediaLinks);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMCutoutPosition.cs b/projects/GKCore/GDModel/GDMCutoutPosition.cs
index b9dc81783..ea240e049 100644
--- a/projects/GKCore/GDModel/GDMCutoutPosition.cs
+++ b/projects/GKCore/GDModel/GDMCutoutPosition.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -126,5 +126,15 @@ internal void SetRawData(int x1, int y1, int x2, int y2)
             fX2 = x2;
             fY2 = y2;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fX1);
+            hashCode.AddVal(fY1);
+            hashCode.AddVal(fX2);
+            hashCode.AddVal(fY2);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMDate.cs b/projects/GKCore/GDModel/GDMDate.cs
index 198c77ac7..9164530ee 100644
--- a/projects/GKCore/GDModel/GDMDate.cs
+++ b/projects/GKCore/GDModel/GDMDate.cs
@@ -698,5 +698,18 @@ private static byte DaysInMonth(bool yearBC, short year, byte month, GDMCalendar
 
             return (byte)DateTime.DaysInMonth(year, month);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fApproximated);
+            hashCode.AddVal(fCalendar);
+            hashCode.AddVal(fDay);
+            hashCode.AddVal(fMonth);
+            hashCode.AddVal(fYear);
+            hashCode.AddVal(fYearBC);
+            hashCode.AddObj(fYearModifier);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMDateInterpreted.cs b/projects/GKCore/GDModel/GDMDateInterpreted.cs
index 3ffe58229..2efe8deee 100644
--- a/projects/GKCore/GDModel/GDMDateInterpreted.cs
+++ b/projects/GKCore/GDModel/GDMDateInterpreted.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2019 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -75,5 +76,12 @@ public override string ParseString(string strValue)
             }
             return result;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDatePhrase);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMDatePeriod.cs b/projects/GKCore/GDModel/GDMDatePeriod.cs
index c224a9504..38391750d 100644
--- a/projects/GKCore/GDModel/GDMDatePeriod.cs
+++ b/projects/GKCore/GDModel/GDMDatePeriod.cs
@@ -185,5 +185,13 @@ public override void GetDateRange(out GDMDate dateStart, out GDMDate dateEnd)
             dateStart = fDateFrom;
             dateEnd = fDateTo;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDateFrom);
+            hashCode.AddObj(fDateTo);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMDateRange.cs b/projects/GKCore/GDModel/GDMDateRange.cs
index 99ad77325..fc84bd34e 100644
--- a/projects/GKCore/GDModel/GDMDateRange.cs
+++ b/projects/GKCore/GDModel/GDMDateRange.cs
@@ -197,5 +197,13 @@ public override void GetDateRange(out GDMDate dateStart, out GDMDate dateEnd)
             dateStart = fDateAfter;
             dateEnd = fDateBefore;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDateAfter);
+            hashCode.AddObj(fDateBefore);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMDateValue.cs b/projects/GKCore/GDModel/GDMDateValue.cs
index f8c7a76c9..b2351e084 100644
--- a/projects/GKCore/GDModel/GDMDateValue.cs
+++ b/projects/GKCore/GDModel/GDMDateValue.cs
@@ -179,5 +179,12 @@ public override void GetDateRange(out GDMDate dateStart, out GDMDate dateEnd)
                 fValue.GetDateRange(out dateStart, out dateEnd);
             }
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fValue);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMFamilyEvent.cs b/projects/GKCore/GDModel/GDMFamilyEvent.cs
index a45bc46da..fdf33fc57 100644
--- a/projects/GKCore/GDModel/GDMFamilyEvent.cs
+++ b/projects/GKCore/GDModel/GDMFamilyEvent.cs
@@ -18,6 +18,8 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
+
 namespace GDModel
 {
     public sealed class GDMFamilyEvent : GDMCustomEvent
@@ -30,5 +32,10 @@ public GDMFamilyEvent(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMFamilyRecord.cs b/projects/GKCore/GDModel/GDMFamilyRecord.cs
index 754ff0e79..d9e7712d8 100644
--- a/projects/GKCore/GDModel/GDMFamilyRecord.cs
+++ b/projects/GKCore/GDModel/GDMFamilyRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -305,5 +305,15 @@ public bool HasChild(GDMIndividualRecord child)
         {
             return IndexOfChild(child) >= 0;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            ProcessHashes(ref hashCode, fChildren);
+            hashCode.AddObj(fHusband);
+            hashCode.AddObj(fWife);
+            hashCode.AddVal(fStatus);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMFileReference.cs b/projects/GKCore/GDModel/GDMFileReference.cs
index 2e7761043..f31b54a12 100644
--- a/projects/GKCore/GDModel/GDMFileReference.cs
+++ b/projects/GKCore/GDModel/GDMFileReference.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -178,5 +178,13 @@ public static GDMMultimediaFormat RecognizeFormat(string fileName)
             var strFmt = GetMultimediaExt(fileName);
             return string.IsNullOrEmpty(strFmt) ? GDMMultimediaFormat.mfUnknown : GEDCOMUtils.GetMultimediaFormatVal(strFmt);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fMultimediaFormat);
+            hashCode.AddVal(fMediaType);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMFileReferenceWithTitle.cs b/projects/GKCore/GDModel/GDMFileReferenceWithTitle.cs
index e49fbb3c9..b70e81bdf 100644
--- a/projects/GKCore/GDModel/GDMFileReferenceWithTitle.cs
+++ b/projects/GKCore/GDModel/GDMFileReferenceWithTitle.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2019 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -54,5 +54,12 @@ public override bool IsEmpty()
         {
             return base.IsEmpty() && string.IsNullOrEmpty(fTitle);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fTitle);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMGroupRecord.cs b/projects/GKCore/GDModel/GDMGroupRecord.cs
index 5f457b9cd..3f3f61d61 100644
--- a/projects/GKCore/GDModel/GDMGroupRecord.cs
+++ b/projects/GKCore/GDModel/GDMGroupRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -160,5 +160,13 @@ public override void MoveTo(GDMRecord targetRecord)
                 targetGroup.Members.Add(obj);
             }
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fGroupName);
+            ProcessHashes(ref hashCode, fMembers);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMIndividualAttribute.cs b/projects/GKCore/GDModel/GDMIndividualAttribute.cs
index 10a39ed29..aa3ef4003 100644
--- a/projects/GKCore/GDModel/GDMIndividualAttribute.cs
+++ b/projects/GKCore/GDModel/GDMIndividualAttribute.cs
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -39,5 +40,12 @@ public GDMIndividualAttribute(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            //hashCode.AddObj(PhysicalDescription); <- inner Tags
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMIndividualEvent.cs b/projects/GKCore/GDModel/GDMIndividualEvent.cs
index 27d9a3afb..5104b903b 100644
--- a/projects/GKCore/GDModel/GDMIndividualEvent.cs
+++ b/projects/GKCore/GDModel/GDMIndividualEvent.cs
@@ -18,6 +18,8 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
+
 namespace GDModel
 {
     public sealed class GDMIndividualEvent : GDMCustomEvent
@@ -30,5 +32,10 @@ public GDMIndividualEvent(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMIndividualLink.cs b/projects/GKCore/GDModel/GDMIndividualLink.cs
index d59f7ee20..819f91e17 100644
--- a/projects/GKCore/GDModel/GDMIndividualLink.cs
+++ b/projects/GKCore/GDModel/GDMIndividualLink.cs
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -36,6 +37,11 @@ public GDMIndividualLink(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 
 
@@ -56,5 +62,10 @@ public GDMChildLink(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMIndividualRecord.cs b/projects/GKCore/GDModel/GDMIndividualRecord.cs
index 97a5daa7c..48281f526 100644
--- a/projects/GKCore/GDModel/GDMIndividualRecord.cs
+++ b/projects/GKCore/GDModel/GDMIndividualRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -565,5 +565,17 @@ public GDMMultimediaLink GetPrimaryMultimediaLink()
 
             return result;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            ProcessHashes(ref hashCode, fAssociations);
+            ProcessHashes(ref hashCode, fChildToFamilyLinks);
+            ProcessHashes(ref hashCode, fGroups);
+            ProcessHashes(ref hashCode, fPersonalNames);
+            ProcessHashes(ref hashCode, fSpouseToFamilyLinks);
+            hashCode.AddVal(fSex);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMInterfaces.cs b/projects/GKCore/GDModel/GDMInterfaces.cs
index d7ff76a38..7b14c54c3 100644
--- a/projects/GKCore/GDModel/GDMInterfaces.cs
+++ b/projects/GKCore/GDModel/GDMInterfaces.cs
@@ -36,6 +36,8 @@ public interface IGDMTag : IGDMObject
         GDMList<GDMTag> SubTags { get; }
 
         bool IsEmpty();
+
+        int GetHashCode();
     }
 
 
diff --git a/projects/GKCore/GDModel/GDMLanguage.cs b/projects/GKCore/GDModel/GDMLanguage.cs
index e109c2646..43101dfbf 100644
--- a/projects/GKCore/GDModel/GDMLanguage.cs
+++ b/projects/GKCore/GDModel/GDMLanguage.cs
@@ -183,5 +183,12 @@ public GDMLanguage(int tagId, string tagValue)
         {
             SetNameValue(tagId, tagValue);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fValue);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMLines.cs b/projects/GKCore/GDModel/GDMLines.cs
index d31bc71dd..b76362d32 100644
--- a/projects/GKCore/GDModel/GDMLines.cs
+++ b/projects/GKCore/GDModel/GDMLines.cs
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using System.Collections.Generic;
 using System.Text;
 
@@ -68,6 +69,17 @@ public GDMLines(string[] list) : this()
             }
         }
 
+        public override int GetHashCode()
+        {
+            var result = new HashCode();
+
+            for (int i = 0, num = base.Count; i < num; i++) {
+                result.AddObj(base[i]);
+            }
+
+            return result.ToHashCode();
+        }
+
         public bool IsEmpty()
         {
             return (base.Count <= 0) || (base.Count == 1 && (base[0] == "" || base[0] == LINE_BREAK));
diff --git a/projects/GKCore/GDModel/GDMLocationLink.cs b/projects/GKCore/GDModel/GDMLocationLink.cs
index 6e9d23090..273488ef2 100644
--- a/projects/GKCore/GDModel/GDMLocationLink.cs
+++ b/projects/GKCore/GDModel/GDMLocationLink.cs
@@ -94,5 +94,13 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             fDate.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDate);
+            hashCode.AddVal(fRelationship);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMLocationName.cs b/projects/GKCore/GDModel/GDMLocationName.cs
index 147209fca..a46523647 100644
--- a/projects/GKCore/GDModel/GDMLocationName.cs
+++ b/projects/GKCore/GDModel/GDMLocationName.cs
@@ -103,5 +103,14 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             fDate.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAbbreviation);
+            hashCode.AddObj(fDate);
+            hashCode.AddVal(fLanguage);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMLocationRecord.cs b/projects/GKCore/GDModel/GDMLocationRecord.cs
index 567b34ef4..6dd8b74ca 100644
--- a/projects/GKCore/GDModel/GDMLocationRecord.cs
+++ b/projects/GKCore/GDModel/GDMLocationRecord.cs
@@ -325,6 +325,15 @@ private static int ElementsCompare(IGDMLocationElement cp1, IGDMLocationElement
             UDN udn2 = cp2.Date.GetUDN();
             return udn1.CompareTo(udn2);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fMap);
+            ProcessHashes(ref hashCode, fNames);
+            ProcessHashes(ref hashCode, fTopLevels);
+        }
     }
 
     public interface IGDMLocationElement
diff --git a/projects/GKCore/GDModel/GDMLocationType.cs b/projects/GKCore/GDModel/GDMLocationType.cs
index fafdaac40..2ed516f5a 100644
--- a/projects/GKCore/GDModel/GDMLocationType.cs
+++ b/projects/GKCore/GDModel/GDMLocationType.cs
@@ -88,5 +88,13 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             fDate.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAbbreviation);
+            hashCode.AddObj(fDate);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMMap.cs b/projects/GKCore/GDModel/GDMMap.cs
index 751426890..b8c4a27ad 100644
--- a/projects/GKCore/GDModel/GDMMap.cs
+++ b/projects/GKCore/GDModel/GDMMap.cs
@@ -71,5 +71,13 @@ public override bool IsEmpty()
         {
             return base.IsEmpty() && (fLati == 0.0d && fLong == 0.0d);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fLati);
+            hashCode.AddVal(fLong);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMMultimediaLink.cs b/projects/GKCore/GDModel/GDMMultimediaLink.cs
index 92a5e59af..2156a88c6 100644
--- a/projects/GKCore/GDModel/GDMMultimediaLink.cs
+++ b/projects/GKCore/GDModel/GDMMultimediaLink.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -164,5 +164,16 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             fFileReferences.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fCutoutPosition);
+            ProcessHashes(ref hashCode, fFileReferences);
+            hashCode.AddVal(fIsPrimary);
+            hashCode.AddVal(fIsPrimaryCutout);
+            hashCode.AddObj(fTitle);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMMultimediaRecord.cs b/projects/GKCore/GDModel/GDMMultimediaRecord.cs
index 416fe686a..b093c51e6 100644
--- a/projects/GKCore/GDModel/GDMMultimediaRecord.cs
+++ b/projects/GKCore/GDModel/GDMMultimediaRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -90,5 +90,12 @@ public string GetFileTitle()
             GDMFileReferenceWithTitle fileRef = fFileReferences[0];
             return fileRef.Title;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            ProcessHashes(ref hashCode, fFileReferences);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMNoteRecord.cs b/projects/GKCore/GDModel/GDMNoteRecord.cs
index 5c9aa082b..a9a62537b 100644
--- a/projects/GKCore/GDModel/GDMNoteRecord.cs
+++ b/projects/GKCore/GDModel/GDMNoteRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -131,5 +131,12 @@ public void SetNoteText(string text)
 
             fLines.Text = text;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fLines);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMNotes.cs b/projects/GKCore/GDModel/GDMNotes.cs
index 5ed4e8eaf..b05117796 100644
--- a/projects/GKCore/GDModel/GDMNotes.cs
+++ b/projects/GKCore/GDModel/GDMNotes.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -83,6 +83,13 @@ public override string ParseString(string strValue)
             fLines.Add(strValue);
             return string.Empty;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fLines);
+        }
     }
 
 
@@ -145,5 +152,12 @@ public override string ParseString(string strValue)
             }
             return result;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fLines);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMPersonalName.cs b/projects/GKCore/GDModel/GDMPersonalName.cs
index fc0a3c1d4..717485e15 100644
--- a/projects/GKCore/GDModel/GDMPersonalName.cs
+++ b/projects/GKCore/GDModel/GDMPersonalName.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -383,5 +383,25 @@ public float IsMatch(GDMPersonalName otherName, bool onlyFirstPart)
 
             return match;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fGiven);
+            hashCode.AddVal(fLanguage);
+            hashCode.AddObj(fNamePrefix);
+            hashCode.AddObj(fNameSuffix);
+            hashCode.AddVal(fNameType);
+            hashCode.AddObj(fNickname);
+            ProcessHashes(ref hashCode, fNotes);
+            ProcessHashes(ref hashCode, fSourceCitations);
+            hashCode.AddObj(fSurnamePrefix);
+            hashCode.AddObj(fSurname);
+            hashCode.AddObj(fPatronymicName);
+            hashCode.AddObj(fMarriedName);
+            hashCode.AddObj(fReligiousName);
+            hashCode.AddObj(fCensusName);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMPlace.cs b/projects/GKCore/GDModel/GDMPlace.cs
index c49141562..07d531a01 100644
--- a/projects/GKCore/GDModel/GDMPlace.cs
+++ b/projects/GKCore/GDModel/GDMPlace.cs
@@ -131,5 +131,15 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             if (fMap != null) fMap.ReplaceXRefs(map);
             if (fNotes != null) fNotes.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fForm);
+            hashCode.AddObj(fLocation);
+            hashCode.AddObj(fMap);
+            ProcessHashes(ref hashCode, fNotes);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMPointer.cs b/projects/GKCore/GDModel/GDMPointer.cs
index cf8601f78..f64275bde 100644
--- a/projects/GKCore/GDModel/GDMPointer.cs
+++ b/projects/GKCore/GDModel/GDMPointer.cs
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -83,5 +84,12 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
                 XRef = map.FindNewXRef(XRef);
             }
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fXRef);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMPointerWithNotes.cs b/projects/GKCore/GDModel/GDMPointerWithNotes.cs
index 0caa1e1e8..bc5bc7a85 100644
--- a/projects/GKCore/GDModel/GDMPointerWithNotes.cs
+++ b/projects/GKCore/GDModel/GDMPointerWithNotes.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -84,5 +84,12 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             if (fNotes != null) fNotes.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            ProcessHashes(ref hashCode, fNotes);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMRecord.cs b/projects/GKCore/GDModel/GDMRecord.cs
index 3eee9b693..295d2fa03 100644
--- a/projects/GKCore/GDModel/GDMRecord.cs
+++ b/projects/GKCore/GDModel/GDMRecord.cs
@@ -317,5 +317,18 @@ public long GetId()
         {
             return GEDCOMUtils.GetXRefNumber(XRef);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAutomatedRecordID);
+            // without fChangeDate and fUID!
+            hashCode.AddObj(fXRef);
+            ProcessHashes(ref hashCode, fMultimediaLinks);
+            ProcessHashes(ref hashCode, fNotes);
+            ProcessHashes(ref hashCode, fSourceCitations);
+            ProcessHashes(ref hashCode, fUserReferences);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMRecordWithEvents.cs b/projects/GKCore/GDModel/GDMRecordWithEvents.cs
index cc5eafae8..99c2cc428 100644
--- a/projects/GKCore/GDModel/GDMRecordWithEvents.cs
+++ b/projects/GKCore/GDModel/GDMRecordWithEvents.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -202,5 +202,13 @@ public int GetChronologicalYear(string eventSign)
             GDMCustomEvent evt = FindEvent(eventSign);
             return (evt == null) ? 0 : evt.GetChronologicalYear();
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            ProcessHashes(ref hashCode, fEvents);
+            hashCode.AddVal(fRestriction);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMRepositoryCitation.cs b/projects/GKCore/GDModel/GDMRepositoryCitation.cs
index 88310e15c..aa0860606 100644
--- a/projects/GKCore/GDModel/GDMRepositoryCitation.cs
+++ b/projects/GKCore/GDModel/GDMRepositoryCitation.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2019 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -28,5 +29,10 @@ public GDMRepositoryCitation()
         {
             SetName(GEDCOMTagType.REPO);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMRepositoryRecord.cs b/projects/GKCore/GDModel/GDMRepositoryRecord.cs
index 7664cfe21..d47f4eef0 100644
--- a/projects/GKCore/GDModel/GDMRepositoryRecord.cs
+++ b/projects/GKCore/GDModel/GDMRepositoryRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -107,5 +107,13 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             if (fAddress != null) fAddress.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAddress);
+            hashCode.AddObj(fRepositoryName);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMResearchRecord.cs b/projects/GKCore/GDModel/GDMResearchRecord.cs
index c0f0bdf8d..ce657fad2 100644
--- a/projects/GKCore/GDModel/GDMResearchRecord.cs
+++ b/projects/GKCore/GDModel/GDMResearchRecord.cs
@@ -311,5 +311,20 @@ public int IndexOfCommunication(GDMCommunicationRecord commRec)
 
             return result;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fResearchName);
+            hashCode.AddVal(fPriority);
+            hashCode.AddVal(fStatus);
+            hashCode.AddObj(fStartDate);
+            hashCode.AddObj(fStopDate);
+            hashCode.AddVal(fPercent);
+            ProcessHashes(ref hashCode, fTasks);
+            ProcessHashes(ref hashCode, fCommunications);
+            ProcessHashes(ref hashCode, fGroups);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSourceCitation.cs b/projects/GKCore/GDModel/GDMSourceCitation.cs
index 640528b95..fe5d9757b 100644
--- a/projects/GKCore/GDModel/GDMSourceCitation.cs
+++ b/projects/GKCore/GDModel/GDMSourceCitation.cs
@@ -233,5 +233,18 @@ public int GetValidCertaintyAssessment()
             int val = fCertaintyAssessment;
             return (val >= 0 && val <= 3) ? val : 0;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fCertaintyAssessment);
+            hashCode.AddObj(fData);
+            hashCode.AddObj(fPage);
+            hashCode.AddObj(fDescription);
+            ProcessHashes(ref hashCode, fMultimediaLinks);
+            ProcessHashes(ref hashCode, fNotes);
+            hashCode.AddObj(fText);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSourceCitationData.cs b/projects/GKCore/GDModel/GDMSourceCitationData.cs
index 092e41944..17638d290 100644
--- a/projects/GKCore/GDModel/GDMSourceCitationData.cs
+++ b/projects/GKCore/GDModel/GDMSourceCitationData.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -88,5 +88,13 @@ public override bool IsEmpty()
         {
             return base.IsEmpty() && fDate.IsEmpty() && fText.IsEmpty();
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDate);
+            hashCode.AddObj(fText);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSourceData.cs b/projects/GKCore/GDModel/GDMSourceData.cs
index b66b3258d..557b96df3 100644
--- a/projects/GKCore/GDModel/GDMSourceData.cs
+++ b/projects/GKCore/GDModel/GDMSourceData.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -101,5 +102,14 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             fEvents.ReplaceXRefs(map);
             if (fNotes != null) fNotes.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAgency);
+            ProcessHashes(ref hashCode, fEvents);
+            ProcessHashes(ref hashCode, fNotes);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSourceEvent.cs b/projects/GKCore/GDModel/GDMSourceEvent.cs
index b0e6ef133..d9e370dd1 100644
--- a/projects/GKCore/GDModel/GDMSourceEvent.cs
+++ b/projects/GKCore/GDModel/GDMSourceEvent.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -84,5 +85,13 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
             base.ReplaceXRefs(map);
             if (fPlace != null) fPlace.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fDate);
+            hashCode.AddObj(fPlace);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSourceRecord.cs b/projects/GKCore/GDModel/GDMSourceRecord.cs
index a688654f1..44d4a8030 100644
--- a/projects/GKCore/GDModel/GDMSourceRecord.cs
+++ b/projects/GKCore/GDModel/GDMSourceRecord.cs
@@ -279,5 +279,19 @@ public GDMRepositoryCitation FindRepository(GDMRepositoryRecord repoRec)
 
             return null;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fData);
+            hashCode.AddObj(fDate);
+            hashCode.AddObj(fOriginator);
+            hashCode.AddObj(fPublication);
+            ProcessHashes(ref hashCode, fRepositoryCitations);
+            hashCode.AddObj(fShortTitle);
+            hashCode.AddObj(fText);
+            hashCode.AddObj(fTitle);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSpouseToFamilyLink.cs b/projects/GKCore/GDModel/GDMSpouseToFamilyLink.cs
index 5bd6fc2bb..579c1e5db 100644
--- a/projects/GKCore/GDModel/GDMSpouseToFamilyLink.cs
+++ b/projects/GKCore/GDModel/GDMSpouseToFamilyLink.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2022 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -34,5 +35,10 @@ public GDMSpouseToFamilyLink(string familyXRef)
             SetName(GEDCOMTagType.FAMS);
             XRef = familyXRef;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSubmissionRecord.cs b/projects/GKCore/GDModel/GDMSubmissionRecord.cs
index 4a3395151..fb42cb0e1 100644
--- a/projects/GKCore/GDModel/GDMSubmissionRecord.cs
+++ b/projects/GKCore/GDModel/GDMSubmissionRecord.cs
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -119,5 +120,17 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
 
             fSubmitter.ReplaceXRefs(map);
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fFamilyFileName);
+            hashCode.AddObj(fTempleCode);
+            hashCode.AddVal(fGenerationsOfAncestors);
+            hashCode.AddVal(fGenerationsOfDescendants);
+            hashCode.AddVal(fOrdinanceProcessFlag);
+            hashCode.AddObj(fSubmitter);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMSubmitterRecord.cs b/projects/GKCore/GDModel/GDMSubmitterRecord.cs
index 851c68401..54998c11a 100644
--- a/projects/GKCore/GDModel/GDMSubmitterRecord.cs
+++ b/projects/GKCore/GDModel/GDMSubmitterRecord.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,6 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+using System;
 using GDModel.Providers.GEDCOM;
 
 namespace GDModel
@@ -118,5 +119,15 @@ public void SetLanguage(int index, string value)
             }
             fLanguages[index].StringValue = value;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fAddress);
+            ProcessHashes(ref hashCode, fLanguages);
+            hashCode.AddObj(fName);
+            hashCode.AddObj(fRegisteredReference);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMTag.cs b/projects/GKCore/GDModel/GDMTag.cs
index bc9a4dba5..edf1552dd 100644
--- a/projects/GKCore/GDModel/GDMTag.cs
+++ b/projects/GKCore/GDModel/GDMTag.cs
@@ -283,6 +283,29 @@ public virtual string ParseString(string strValue)
         }
 
         #endregion
+
+        protected static void ProcessHashes<T>(ref HashCode hashCode, GDMList<T> tags) where T : GDMTag
+        {
+            if (tags == null) return;
+
+            for (int i = 0; i < tags.Count; i++) {
+                var tag = tags[i];
+                tag.ProcessHashes(ref hashCode);
+            }
+        }
+
+        protected virtual void ProcessHashes(ref HashCode hashCode)
+        {
+            hashCode.AddVal(fId);
+            ProcessHashes(ref hashCode, fTags);
+        }
+
+        public override int GetHashCode()
+        {
+            var result = new HashCode();
+            ProcessHashes(ref result);
+            return result.ToHashCode();
+        }
     }
 
 
@@ -326,5 +349,12 @@ public override string ParseString(string strValue)
             fStringValue = strValue;
             return string.Empty;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fStringValue);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMTaskRecord.cs b/projects/GKCore/GDModel/GDMTaskRecord.cs
index 66d7b9d2e..6aa6d3a12 100644
--- a/projects/GKCore/GDModel/GDMTaskRecord.cs
+++ b/projects/GKCore/GDModel/GDMTaskRecord.cs
@@ -120,5 +120,15 @@ public override void ReplaceXRefs(GDMXRefReplacer map)
                 fGoal = GEDCOMUtils.EncloseXRef(map.FindNewXRef(GEDCOMUtils.CleanXRef(fGoal)));
             }
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fGoal);
+            hashCode.AddVal(fPriority);
+            hashCode.AddObj(fStartDate);
+            hashCode.AddObj(fStopDate);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMTime.cs b/projects/GKCore/GDModel/GDMTime.cs
index 681bea06c..0fffe8cdb 100644
--- a/projects/GKCore/GDModel/GDMTime.cs
+++ b/projects/GKCore/GDModel/GDMTime.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2019 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -115,5 +115,15 @@ internal void SetRawData(byte hour, byte minutes, byte seconds, short fraction)
             fSeconds = seconds;
             fFraction = fraction;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddVal(fHour);
+            hashCode.AddVal(fMinutes);
+            hashCode.AddVal(fSeconds);
+            hashCode.AddVal(fFraction);
+        }
     }
 }
diff --git a/projects/GKCore/GDModel/GDMUserReference.cs b/projects/GKCore/GDModel/GDMUserReference.cs
index 02b8ebf95..57dc5a379 100644
--- a/projects/GKCore/GDModel/GDMUserReference.cs
+++ b/projects/GKCore/GDModel/GDMUserReference.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2021 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -60,5 +60,12 @@ public override void Assign(GDMTag source)
 
             fReferenceType = srcUserRef.fReferenceType;
         }
+
+        protected override void ProcessHashes(ref HashCode hashCode)
+        {
+            base.ProcessHashes(ref hashCode);
+
+            hashCode.AddObj(fReferenceType);
+        }
     }
 }
diff --git a/projects/GKCore/GKCore/HashCode.cs b/projects/GKCore/GKCore/HashCode.cs
index 2abd1da82..d1cfe818d 100644
--- a/projects/GKCore/GKCore/HashCode.cs
+++ b/projects/GKCore/GKCore/HashCode.cs
@@ -68,10 +68,12 @@ private static unsafe uint GenerateGlobalSeed()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void Initialize(out uint v1, out uint v2, out uint v3, out uint v4)
         {
-            v1 = s_seed + Prime1 + Prime2;
-            v2 = s_seed + Prime2;
-            v3 = s_seed;
-            v4 = s_seed - Prime1;
+            unchecked {
+                v1 = s_seed + Prime1 + Prime2;
+                v2 = s_seed + Prime2;
+                v3 = s_seed;
+                v4 = s_seed - Prime1;
+            }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -83,35 +85,45 @@ private static uint RotateLeft(uint value, int offset)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint Round(uint hash, uint input)
         {
-            return RotateLeft(hash + input * Prime2, 13) * Prime1;
+            unchecked {
+                return RotateLeft(hash + input * Prime2, 13) * Prime1;
+            }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint QueueRound(uint hash, uint queuedValue)
         {
-            return RotateLeft(hash + queuedValue * Prime3, 17) * Prime4;
+            unchecked {
+                return RotateLeft(hash + queuedValue * Prime3, 17) * Prime4;
+            }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint MixState(uint v1, uint v2, uint v3, uint v4)
         {
-            return RotateLeft(v1, 1) + RotateLeft(v2, 7) + RotateLeft(v3, 12) + RotateLeft(v4, 18);
+            unchecked {
+                return RotateLeft(v1, 1) + RotateLeft(v2, 7) + RotateLeft(v3, 12) + RotateLeft(v4, 18);
+            }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint MixEmptyState()
         {
-            return s_seed + Prime5;
+            unchecked {
+                return s_seed + Prime5;
+            }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint MixFinal(uint hash)
         {
-            hash ^= hash >> 15;
-            hash *= Prime2;
-            hash ^= hash >> 13;
-            hash *= Prime3;
-            hash ^= hash >> 16;
+            unchecked {
+                hash ^= hash >> 15;
+                hash *= Prime2;
+                hash ^= hash >> 13;
+                hash *= Prime3;
+                hash ^= hash >> 16;
+            }
             return hash;
         }
 
@@ -150,7 +162,7 @@ public void AddHash(int value)
             // To see what's really going on here, have a look at the Combine
             // methods.
 
-            uint val = (uint)value;
+            uint val = unchecked((uint)value);
 
             // Storing the value of _length locally shaves of quite a few bytes
             // in the resulting machine code.
@@ -213,7 +225,7 @@ public int ToHashCode()
             }
 
             hash = MixFinal(hash);
-            return (int)hash;
+            return unchecked((int)hash);
         }
     }
 }
diff --git a/projects/GKCore/GKCore/NetDiff/DiffUtil.cs b/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
index 661d85b66..784204e25 100644
--- a/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
+++ b/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
@@ -18,6 +18,7 @@ public enum DiffStatus
         Deleted,
         Inserted,
         Modified,
+        DeepModified,
     }
 
 
@@ -186,10 +187,15 @@ public static char GetStatusChar(DiffStatus status)
         {
             switch (status)
             {
-                case DiffStatus.Equal: return '=';
-                case DiffStatus.Deleted: return '-';
-                case DiffStatus.Inserted: return '+';
-                case DiffStatus.Modified: return '≠';
+                case DiffStatus.Equal:
+                    return '=';
+                case DiffStatus.Deleted:
+                    return '-';
+                case DiffStatus.Inserted:
+                    return '+';
+                case DiffStatus.Modified:
+                case DiffStatus.DeepModified:
+                    return '≠';
             }
 
             throw new System.Exception();
diff --git a/projects/GKCore/GKCore/Tools/SyncTool.cs b/projects/GKCore/GKCore/Tools/SyncTool.cs
index 765e326bd..019225c53 100644
--- a/projects/GKCore/GKCore/Tools/SyncTool.cs
+++ b/projects/GKCore/GKCore/Tools/SyncTool.cs
@@ -70,9 +70,16 @@ private void CheckModified()
             foreach (var diffRes in Results) {
                 if (diffRes.Status != DiffStatus.Equal) continue;
 
-                if ((diffRes.Obj1.XRef != diffRes.Obj2.XRef) || (diffRes.Obj1.ChangeDate.ChangeDateTime != diffRes.Obj2.ChangeDate.ChangeDateTime)) {
+                var rec1 = diffRes.Obj1;
+                var rec2 = diffRes.Obj2;
+
+                if ((rec1.XRef != rec2.XRef) || (rec1.ChangeDate.ChangeDateTime != rec2.ChangeDate.ChangeDateTime)) {
                     diffRes.Status = DiffStatus.Modified;
                 }
+
+                if (rec1.GetHashCode() != rec2.GetHashCode()) {
+                    diffRes.Status = DiffStatus.DeepModified;
+                }
             }
         }
 
diff --git a/projects/plugins/GKTreeSyncPlugin/TSForm.cs b/projects/plugins/GKTreeSyncPlugin/TSForm.cs
index 65b6992be..264160c79 100644
--- a/projects/plugins/GKTreeSyncPlugin/TSForm.cs
+++ b/projects/plugins/GKTreeSyncPlugin/TSForm.cs
@@ -125,9 +125,10 @@ private void UpdateLists()
                         break;
 
                     case DiffStatus.Modified:
+                    case DiffStatus.DeepModified:
                         item1 = diffChar + " " + compRes.Obj1.XRef;
                         item2 = diffChar + " " + compRes.Obj2.XRef;
-                        backColor = Color.Yellow;
+                        backColor = (compRes.Status == DiffStatus.Modified) ? Color.Yellow : Color.Orange;
                         break;
                 }