Does your group’s DataTemplate use a GroupPanel? If so, you must set the go:Node.LocationElementName to refer to that GroupPanel.
The reason is that the Location of the group has to be the Location of the GroupPanel.
But the Position of the group, i.e. the top-left corner of the group’s Bounds, typically has smaller X and Y values than the Location. This is because of any border or any other elements such as text that surround or are positioned above the GroupPanel.
Your problem is because you are confusing Location with Position. The Node.Move method takes a new position, not a new location. Try replacing “myDiagram.SelectedGroup.Location.X” with “myDiagram.SelectedGroup.Position.X” in your code.
It sounds like I really confused those concepts and practically I changed my code according to your suggestion, and I got it working properly. Thanks a lot!