SlateUI - SMenuAnchor Dropdown Menu Flickering

Hi forum,

I’ve encountered a problem with slate combo menus:
Menus opened with EPopupMethod::CreateNewWindow flickers when it tries to move to a new position after opening, for example when the parent window is dragged to a new position and the menu window tries to follow. This seems to have been fixed in the editor but can still be reproduced in SlateViewer.
The problem also affects SComboBox and SComboButton since both of them are sub-classes of SMenuAnchor.

Any idea how to resolve this?