Inconsistent experience deleting themes in theme KCMs (including the current theme)
Currently, some KCMs don't let you delete themes at all:
- Application Style: no delete button is shown.
- System Sounds: no delete button is shown.
- Window Decorations: no delete button is shown.
Other KCMs do let you delete themes, and let you delete the currently active one.
What happens when you click the currently active theme's delete button? Each KCM seems to handle it differently:
- Boot Splash Screen: The deleted theme is deleted immediately without waiting for you to click Apply. Nothing else in the KCM becomes visually selected.
- Colors: The item that comes next in the grid view gets selected.
- Cursors: "Breeze" gets selected
- Global Themes: the Delete buttons is disabled (I lied, this KCM doesn't actually let you delete the active theme).
- Icons: The item that comes next in the grid view gets selected.
- Plasma Style: The item that comes next in the grid view gets selected.
- Splash Screen: Nothing. But then if you click Apply, a header message appears saying "You cannot delete the currently selected splash screen."
- SDDM: The deleted theme is deleted immediately without waiting for you to click Apply. Nothing else in the KCM becomes visually selected.
All in all it feels fairly incoherent.
My sense is that it would be best to always show a delete button, but disable it for themes installed at a systemwide level by packages, or for the active theme. And then hovering it would show a tooltip explaining why the button is disabled. In other words, I think only the Global Themes KCM comes close to getting this right.