STEPS TO REPRODUCE 1- Create a generic text. 2- Open it. 3- Close your text editor. 4- Try to delete the file with Delete key, or try to open with the Enter key. OBSERVED RESULT The file is not fully focused exactly as it was before the window opened. EXPECTED RESULT The file should be fully focused exactly as it was before the window opened, as if nothing happened.
The same thing happens with Dolphin. If you press the Delete key there, it will activate the Selection Mode.
Dolphin and Plasma are different and have different behaviors. IIRC the Dolphin behavior is intentional rught now, so if you don't like it, please open a separate bug report for it. The Plasma desktop thing is already fixed in Plasma 6.3.0.