[Linux] [1.12.2] Full screen view goes blank when a new file is created in current folder

[FM33]

Hello,

Full screen view goes blank when a new file is created in current folder by external app.

To reproduce :
- Start processing queue from a raw photo editor
- Go to the output folder while processing queue is still running
- Go into fullscreen view on any available picture
- When a new file is being created by external software, XnView switches to it and shows a blank screen

New files should not disturb the use of the application.

There were no issue in older versions.