Hello Zuzana Zelenáková ,

I think you need to reset Studio to resolve this 

1. Close Studio
   2. Go to C:\Users\username\AppData\Roaming\SDL\SDLTrados Studio
   3. Rename the 15.0.0.0 folder (to 15.0.0.0_old for example)
   4. Restart Studio and the issue should be resolved.

You can also use the following free app from SDL App Store (FreshStart)

https://appstore.sdl.com/language/app/sdl-freshstart/876/

Please let us know if this resolved the issue for you.

Hi, 

your solution worked! I reset Studio and it´s working normally. 

Thank you very much.

Zuzana

It's 2025 and I believe I found a much better, simpler fix for this particular problem: Simply go into editor - you don't even need a project open - then to view and select reset window layout. Instantly resolved this problem without a restart. Prior to that I had tried opening individual files within the project and batches of files just to see if that helped, but the mention of 'pane' was a tip off for me. In other threads, many problems are solved by reseting the window layout. Hope this helps!