When you make any edit in action list in Clipboard manager, the Apply button is not activated. STEPS TO REPRODUCE 1. Open Clipboard -> Configure Clipboard. Go to Actions tab. 2. Make any edit in the action list, such as editing description of some action. For example, your description was "description", make it "description 2". OBSERVED RESULT The Apply button is still inactive. But editions are not applied. If you select a text that corresponds action regular expression, you still see that it's description is "description", but not "description 2". EXPECTED RESULT The Apply button activates after making an edit. So you can hit it and apply changes. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.23.2 KDE Frameworks Version: 5.87.0 Qt Version: 5.15.2 Graphics Platform: X11 ADDITIONAL INFORMATION If you want to apply edits without hitting ok (because it leads to window closing), workaround is to toggle some checkbox, for example "Enable MIME-based actions". Then Apply button is activated and you can apply your actions edits.
I noticed that in plasma 5.26.3 there is no more this bug. The tabs were reworked by this commit https://invent.kde.org/plasma/plasma-workspace/-/commit/4ba66e7ed0d0b858a495fe8e2d75b51c38805067 Now there are Action Menu and Actions Configuration tabs. And in Action Configuration the Apply button activates at action description change. I tested it in X11 session. On Wayland unfortunately, the action is not triggered in the same conditions, but this is another bug.