Claude Brindamour 

Unfortunately I suppose, the culprit here is Windows or a damage of your monitor. The steps you've taken make it nearly impossible to search the cause of this behaviour in Trados Studio itself.

As you updated Windows before, I would now try to check, if your graphics driver is up to date. If you, maybe you can restore the previous Windows state using system restore point. Should this not help, check another screen, if possible. Otherwise I really would suppose a monitor damage here.

Problem is ongoing. I do not think it has to do with my screens.

Claude Brindamour 

NET framework is not responsible for display, afaik. The culprit might be outdated graphics driver. How old is your PC? Have you checked all cable connections? It really seems to be a hardware or driver problem.

Claude Brindamour 

NET framework is not responsible for display, afaik. The culprit might be outdated graphics driver. How old is your PC? Have you checked all cable connections? It really seems to be a hardware or driver problem.

My PC is about 1 year old
Processeur    12th Gen Intel(R) Core(TM) i7-12700 (2.10 GHz)
Mémoire vive installée    32,0 Go (31,8 Go utilisable)
Carte graphique    Intel(R) UHD Graphics 770 (128 Mo)
Type du système    Système d’exploitation 64 bits, processeur x64

I'm veryfing graphic drivers. The problem looks major but I judst don't understand all this zooming, up and down and left to right.

After multiple researches, I found out that the culprit was one of my screens that was connected through a displayLink station. There were multiple problems with Trados when using this material. I proceeded to install the latest driver and everything is working out. And I will connect the monitor directly to the computer. 

Claude Brindamour 

Thank you for confirming the hardware problem. Might be very helpful for other people, if they run into a similar problem.

And now I have to reject my own solution answer. :)  Looks like the problem is linked with an update from Intel, regarding UHD Graphics 770 and the recent june driver. There is an incompatibility with the Trados Studio renderer. Many users have been complaining about graphic instabilities similar to these ones (blinking, windows moving on their own). So a little help from INTEL would be great.