Duplicate "ghost" widgets are created when wrapping multiple widgets with a vertical box (From the Hierarchy panel)

If the user selects multiple widget within the hierarchy panel and then right clicks > Wrap with > Vertical box this will create an extra set of the widget that were selected. These widgets will have the same names as their counter parts and will change as their counter parts change. However, if you delete the originals the new "ghost" widgets cannot be deleted.

Pictures attached for reference.

1. Open blank project
2. Create a new Widget blueprint
   Right click content browser > User Interface > Widget Blueprint
3. Open the new widget
4. Add a Button and a Text block to the designer tab
5. Select both widgets in the hierarchy panel (ctrl+ Left click)
6. Wrap the selected widgets with a vertical box
   Right click selected widgets > Wrap with > Vertical box
7. Notice that the widgets have been duplicated

Duplicate ghost widgets when wrapping multple selected widgets in the UMG editor