In case you can’t find a satisfactory workaround, consider sharing some details regarding what you’re trying to achieve. There might be alternatives available.
I want a selection box in a RTS-like manner, so you drag a box and select units in it. That should not be possible on the whole screen, only where is no other UI.
So I use a border to mark the area where this is possible. I need to unhandle mouse down, so normal single selection can take place also (which is in pawn logic, i know bad architecture). The problems are that
What this thread is about
That I need to click on that border first to get it focussed
OnMouseMove doesn’t trigger while Mouse Button Down
Pointer Event → GetScreenSpacePosition returns absolute coords (from OS desktop origin) which is bad for PIE or Windowed. Since drawing of the box occurs in a HUD-class and I pass the event information in my UMG Graph to this class (c++), I use VirtualDesktopToViewportPixel to convert it to viewport coords, but the conversion has no effect other than completely disabling any drawing (why ever).
I thought, since the mouse click is not realyy in a UI manner and is semantically linked to the in-game world, i catch the mouse events inside the pawn and pass it to the hud, completely omitting UMG. I will then have to find a possibility to only allow selection outside from UMG Widgets.