Fix exception when exiting with MapForm or SoundDebugForm open.

Bug #2127145.

Author: rwf-rr

Source/RunActivity/Viewer3D/Processes/GameStateViewer3D.cs

@@ -131,10 +131,7 @@ internal override void Dispose()
                 MPManager.Client.Stop();
             if (Program.Simulator != null)
                 Program.Simulator.Stop();
-            if (Program.MapForm != null)
-                Program.MapForm.Dispose();
-            if (Program.SoundDebugForm != null)
-                Program.SoundDebugForm.Dispose();
+            // MapForm and SoundDebugForm run in the Renderer thread and need to be disposed there
             base.Dispose();
         }
 

Source/RunActivity/Viewer3D/Processes/RenderProcess.cs

@@ -359,6 +359,12 @@ internal void EndDraw()
         internal void Stop()
         {
             Game.WatchdogProcess.Unregister(WatchdogToken);
+
+            // these run in the Renderer thread, and thus cannot be disposed in GameStateViewer3D
+            if (Program.MapForm != null)
+                Program.MapForm.Dispose();
+            if (Program.SoundDebugForm != null)
+                Program.SoundDebugForm.Dispose();
         }
 
         static void SwapFrames(ref RenderFrame frame1, ref RenderFrame frame2)