Prevent editor freez when dragging window

We have a Composure workflow in editor and must be able to drag around windows without the editor freezing.
I found 2 different behaviors.

1: Freez when dragging a editor tab
This I was able to resolve with console “slate.bAllowThrottling 0”

2: Freez when dragging the actual window
Here the entire prozess seems to freez. I put a breakpoint in Launch.cpp
while( !IsEngineExitRequested() )
EngineTick(); // Breakpoint
and even that is not reached anymore when dragging the window.
It could also get stuck in an inner loop but don’t know where to look anymore.