Linux Desktop App strange case...

A question to the linux specialists…

I wonder about my desktop app running on centOS 7.
It just read some information from text and picture files in a specified folder and put the data into a valentina database.
Actually it works fine.
But there is a thing I do not understand…
As I could see while feeding the folder with files, the app window disapeard, like it crashed.
No error, nothing.
But the files in the folder were processed anyway.
I thought it was a problem of GUI delay.
But after that I put more files to the folder and they were processed as well, even I cannot find anything of the app!?

Anyone knows what is going on here?

depending on how you’ve done this the UI may be unresponsive and unable to repaint while it is processing

moving the processing to a thread should resolve that