Using a pen stylus to close the document information window with the "window close" titlebar button [X] causes Krita to crash immediately, losing any unsaved work. By using a mouse this doesn't happen.

Build: Win-x64 2.7.8.18

Reproducible: Always

Steps to Reproduce:
1. Create a new image
2. File>Document Information
3. Click the [X] close windows button with a pen tablet
Actual Results:  
The program crashes.

Expected Results:  
The Document Information window should get safely closed.

Relevant output from Debugview when Krita crashes in that way:

[8024] CRITICAL: According to statistics of the KisTileDataStore some tiles have leaked from the Krita control! 
[8024] CRITICAL: Tiles in memory: 3 Total tiles: 3 
[8024] QWaitCondition: Destroyed while threads are still waiting
[8024] QWaitCondition: Destroyed while threads are still waiting