Drag and drop a file within dolphin window, and the user is given a pop-up menu to move/copy/link. If the user decides to ignore the menu and close it, Dolphin displays a very prominent error message that slides down from the top saying "user canceled action". Is that really necessary? In my opinion, that message is invasive, does not offer much value, does not close with escape key and is an inconvenience.
Thanks for the bug report! This should already be fixed by https://invent.kde.org/system/dolphin/-/commit/a44830c3a9f954c376d21d4526d94c26d19d010c. So if you update to Dolphin version 22.08 at some point you shouldn't be affected by this bug anymore.