DYN-4449 Undo in group casues weird visual artifacts (#15067)

* DYN-4449 fixed

connectors in groups remain collapsed on undo

* DYN-4449-update

second PR attempt

* DYN-4449-Unit test added

src/DynamoCoreWpf/ViewModels/Core/ConnectorViewModel.cs

@@ -71,7 +71,7 @@ public partial class ConnectorViewModel : ViewModelBase
         public List<Point[]> BezierControlPoints { get; set; }
 
         /// <summary>
-        /// Property tracks 'X' location from mouse poisition
+        /// Property tracks 'X' location from mouse position
         /// </summary>
         public double PanelX
         {
@@ -119,7 +119,7 @@ public Point MousePosition
         }
 
         /// <summary>
-        /// This WatchHoverViewModel controls the visibility and behaviour of the WatchHoverIcon
+        /// This WatchHoverViewModel controls the visibility and behavior of the WatchHoverIcon
         /// which appears when you hover over this connector.
         /// </summary>
         public ConnectorAnchorViewModel ConnectorAnchorViewModel
@@ -537,7 +537,7 @@ public PreviewState PreviewState
 
         /// <summary>
         /// Toggle used to turn Connector PreviewState to the correct state when a pin is selected.
-        /// Modelled after connector preview behaviour when a node is selected.
+        /// Modelled after connector preview behavior when a node is selected.
         /// </summary>
         public bool AnyPinSelected
         {
@@ -1371,7 +1371,7 @@ private void HandlePinModelChanged(object sender, NotifyCollectionChangedEventAr
         /// <summary>
         ///  Removes all connectorPinViewModels/ connectorPinModels. This occurs during 'dispose'
         /// operation as well as during the 'PlaceWatchNode', where all previous pins corresponding 
-        /// to a connector are cleareed.
+        /// to a connector are cleared.
         /// </summary>
         /// <param name="allDeletedModels"> This argument is used when placing a WatchNode from ConnectorAnchorViewModel. A reference
         /// to all previous pins is required for undo/redo recorder.</param>
@@ -1426,9 +1426,24 @@ public void Redraw()
                 this.Redraw(this.ConnectorModel.End.Center);
             }
 
+            this.SetCollapsedByNodeViewModel();
             RaisePropertyChanged(nameof(ZIndex));
         }
 
+        /// <summary>
+        /// Evaluates whether both nodes associated with a connector are collapsed, if so, collapses the connector itself.
+        /// This is to address DYN-4449.  Connectors are only recorded in the Undo stack when they are connected.
+        /// Consequently, if a group is collapsed and then moved, performing an Undo operation will not restore
+        /// the connector to its state at the time the move was recorded.
+        /// </summary>
+        private void SetCollapsedByNodeViewModel()
+        {
+            if (this.Nodevm.IsCollapsed && this.NodeEnd.IsCollapsed)
+            {
+                this.IsCollapsed = true;
+            }
+        }
+
         /// <summary>
         /// Recalculate the connector's points given the end point
         /// </summary>

test/DynamoCoreWpfTests/AnnotationViewModelTests.cs

@@ -1427,6 +1427,58 @@ public void CanToggleVisibilityOfAllNodesInAGroup()
             Assert.AreEqual(true, ViewModel.CurrentSpaceViewModel.HasUnsavedChanges);
         }
 
+        [Test]
+        public void ConnectorsRemainCollapsedOnUndoCollapsedGroup()
+        {
+            // Arrange
+            var parentGroupName = "parentGroup";
+
+            OpenModel(@"core\annotationViewModelTests\connectorsRemainCollapsedAfterUndo.dyn");
+
+            var parentGroupVM = ViewModel.CurrentSpaceViewModel.Annotations.FirstOrDefault(x => x.AnnotationText == parentGroupName);
+            var connectors = ViewModel.CurrentSpaceViewModel.Connectors;
+
+            // Assert group exists and connectors are expanded
+            Assert.IsNotNull(parentGroupVM);
+            Assert.AreEqual(0, connectors.Count(c => c.IsCollapsed));
+
+            // Act
+            // Collapse the parent group
+            parentGroupVM.IsExpanded = false;
+
+            // Assert connectors are collapsed
+            Assert.AreEqual(2, connectors.Count(c => c.IsCollapsed));
+
+            // Select the all nodes from parent group and move them
+            DynamoSelection.Instance.Selection.Clear();
+            parentGroupVM.SelectAll();
+
+            // Perform move operation
+            var initialGroupX = parentGroupVM.Left;
+            var initialGroupY = parentGroupVM.Top;
+
+            var operation = DynamoModel.DragSelectionCommand.Operation.BeginDrag;
+            var command = new DynamoModel.DragSelectionCommand(new Point2D(100, 100), operation);
+
+            ViewModel.ExecuteCommand(command);
+
+            operation = DynamoModel.DragSelectionCommand.Operation.EndDrag;
+            command = new DynamoModel.DragSelectionCommand(new Point2D(300, 300), operation);
+
+            ViewModel.ExecuteCommand(command);
+
+            // Assert the group has moved and connectors remain collapsed
+            Assert.AreNotEqual(initialGroupX, parentGroupVM.Left);
+            Assert.AreNotEqual(initialGroupY, parentGroupVM.Top);
+            Assert.AreEqual(2, connectors.Count(c => c.IsCollapsed));
+
+            // Undo move operation
+            ViewModel.UndoCommand.Execute(null);
+
+            // Assert connectors remain collapsed post-undo
+            Assert.AreEqual(2, connectors.Count(c => c.IsCollapsed));
+        }
+
         #endregion
     }
 }