DYN-6176 Retain selected nodes/groups when dragging it into a group

src/DynamoCoreWpf/Utilities/CompactBubbleHandler.cs

@@ -25,7 +25,7 @@ public static CompactBubbleViewModel Process(MirrorData value)
         {
             items = 0;
             var viewModel = ProcessThing(value, true);
-            viewModel.SetObjectType(value.Data);
+            viewModel.SetObjectType(value?.Data);
             viewModel.NumberOfItems = items;
 
             return viewModel;

src/DynamoCoreWpf/ViewModels/Core/AnnotationViewModel.cs

@@ -642,7 +642,7 @@ public AnnotationViewModel(WorkspaceViewModel workspaceViewModel, AnnotationMode
 
             ViewModelBases = this.WorkspaceViewModel.GetViewModelsInternal(annotationModel.Nodes.Select(x => x.GUID));
 
-            // Add all grouped AnnotaionModels to the CutGeometryDictionary.
+            // Add all grouped AnnotationModels to the CutGeometryDictionary.
             // And raise ZIndex changed to make sure nested groups have
             // a higher zIndex than the parent.
             using (NestedGroupsGeometries.DeferCollectionReset())

src/DynamoCoreWpf/ViewModels/Core/StateMachine.cs

@@ -761,7 +761,7 @@ internal bool HandleMouseRelease(object sender, MouseButtonEventArgs e)
                             .ToList();
 
                         // AddModelsToGroupModelCommand adds models to the selected group
-                        // therefor we add the dropGroup to the selection before calling
+                        // therefore we add the dropGroup to the selection before calling
                         // the command.
                         DynamoSelection.Instance.Selection.AddUnique(dropGroup.AnnotationModel);
 
@@ -794,7 +794,9 @@ internal bool HandleMouseRelease(object sender, MouseButtonEventArgs e)
                             owningWorkspace.DynamoViewModel.AddModelsToGroupModelCommand.Execute(null);
                         }
                         dropGroup.NodeHoveringState = false;
-                        dropGroup.SelectAll();
+                        //select only those models which were added to the group
+                        DynamoSelection.Instance.ClearSelection();
+                        DynamoSelection.Instance.Selection.AddRange(modelsToAdd);
                     }
 
                     SetCurrentState(State.None); // Dragging operation ended.