Crash or main scene window goes black when drag it or dock it.

[AbdallahFH]

Release Type: Official Release

Version: 4.2.0.2067

Platform(s): Windows

Describe the bug
The game studio crash or the main scene window goes black (stop rendering maybe) when you drag it outside or dock it.
the workaround for this bug is just close the window and reopen it.
To Reproduce
Steps to reproduce the behavior:

1. Drag main scene window or dock it, it may crash or stop rendering.
   Screenshots
   
   Crash Log
   log.txt

[Eideren]

Likely caused by #1897