[GraphEditor] Node: Display connected children when the parent is collapsed

Just like any other connected attribute, any child attribute within a
Group that is either the source or destination of an edge needs to remain
on display, independently from the status of its parent (collapsed or
expanded).

Author: cbentejac

meshroom/ui/qml/GraphEditor/Node.qml

@@ -126,9 +126,10 @@ Item {
          * it is reset.
          */
         if (Boolean(attribute.enabled)) {
-            // If the parent's a GroupAttribute, use status of the parent's pin to determine visibility
+            // If the parent's a GroupAttribute, use status of the parent's pin to determine visibility UNLESS the
+            // child attribute is already connected
             if (attribute.root && attribute.root.type === "GroupAttribute") {
-                var visible = Boolean(parentPins.get(attribute.root.name))
+                var visible = Boolean(parentPins.get(attribute.root.name) || attribute.hasOutputConnections || attribute.isLinkNested)
                 if (!visible && parentPins.has(attribute.name) && parentPins.get(attribute.name) === true) {
                     parentPins.set(attribute.name, false)
                     pin.expanded = false
@@ -459,7 +460,8 @@ Item {
                                     visible: {
                                         if (Boolean(modelData.enabled || modelData.hasOutputConnections)) {
                                             if (modelData.root && modelData.root.type === "GroupAttribute") {
-                                                return Boolean(outputs.parentPins.get(modelData.root.name))
+                                                return Boolean(outputs.parentPins.get(modelData.root.name) ||
+                                                               modelData.hasOutputConnections || modelData.isLinkNested)
                                             }
                                             return true
                                         }
@@ -520,7 +522,8 @@ Item {
                                     visible: {
                                         if (Boolean(modelData.enabled)) {
                                             if (modelData.root && modelData.root.type === "GroupAttribute") {
-                                                return Boolean(inputs.parentPins.get(modelData.root.name))
+                                                return Boolean(inputs.parentPins.get(modelData.root.name) ||
+                                                               modelData.hasOutputConnections || modelData.isLinkNested)
                                             }
                                             return true
                                         }
@@ -607,7 +610,8 @@ Item {
                                         visible: {
                                             if (Boolean(modelData.enabled || modelData.isLinkNested || modelData.hasOutputConnections)) {
                                                 if (modelData.root && modelData.root.type === "GroupAttribute") {
-                                                    return Boolean(inputParams.parentPins.get(modelData.root.name))
+                                                    return Boolean(inputParams.parentPins.get(modelData.root.name) ||
+                                                                   modelData.hasOutputConnections || modelData.isLinkNested)
                                                 }
                                                 return true
                                             }