So, when the wastebin icon bug started happening again the other day (after it seemed to have gone away forever), I set out to really do some heavy testing, and I’ve finally figured out the “pattern” or the “right conditions”:
- Make sure the wastebin both is and looks empty.
- Put a file on the desktop.
- Double-click the wastebin icon on the desktop so that a Dolphin window opens showing the empty wastebin.
- Delete the file from the desktop by either pressing “Delete”, moving it into the wastebin icon, moving it into the wastebin Dolphin window, or by selecting “Move to Wastebin” from its context menu.
- The wastebin will now switch its icon to look full, and the file appears in the wastebin Dolphin window. (So far, so good.)
- Now empty the wastebin by either clicking “Empty Wastebin” in the wastebin Dolphin window, or by the wastebin’s context menu.
- The wastebin will be emptied but the icon will remain looking “full”, no matter what you do, including pressing F5 on the desktop. The only way to get it to look empty now seems to be to delete another file (with the wastebin Dolphin window closed) and then empty it again.
This must be why it felt so “random”; I didn’t always have the wastebin opened in Dolphin.
Important: This only happens if the wastebin Dolphin window was open when the file was deleted. If you start off with no wastebin Dolphin window and then open the wastebin Dolphin window and empty it, the icon does revert back to looking empty (as it should).
Possibly this has been fixed in Plasma 6 and I’m just reporting “old news”, but maybe this has some value to you. I can’t be the only one “stuck with” Plasma 5. (Also, some fixes do seem to trickle down even on Debian stable; it’s not completely frozen in time.)