That is exactly the issue I am trying to point out (for executable files like .desktop), see post 3 and now with screenshots:
Unfortunately, taking a screenshot is impossible, it doesn’t work when the right-click context menu of a file is open. So you have to trust me:
Whatever I do, that “Open With…” list ALWAYS contains GEdit and TextWriter, no matter of the settings, for example:
Pluma is not shown in “Open with…”
Like this, by making GEdit Default again, Pluma DOES appear in the list!
The only strange behaviour remaining:
When I hit “Reset to system defaults”, Pluma is the default again (like screenshot 1) and it does not appear in the list.
For now this (2nd screenshot) solves the issue for me, but it seems contra-intuitive. Especially if I would remove GEdit, would Pluma become the default app in this overview? And then it would probably disappear again from the context menu?