Dragging the 2docked windows of WinBoard 4.8.0 'Game Viewer' will alternatively press and unpress the applications taskbar pane

Expected result
The taskbar pane should not alternate between pressed and unpressed state when dragging the window
2k3sp2_taskbarIcon_ok_while_dragging.webm

Observed result
It does.
0.4.13-RC-48-g818e5bc.log
0.4.13-RC-48-g818e5bc.webm

This can be reproduced even right after starting up the main app from startmenu "game viewer".
No additional steps are required to be performed from within the application beforehand.
My naive interpretation of what I see is, that this is caused by the fact that the application glues/docks two different windows together.

Eventually this is also the reason for CORE-16349