KDE trashcan reports "empty" when it is not

I just upgraded to trusty tahr. At first, the desktop trash icon wouldn't even open the trash:/ items, it said "invalid url".
First, I cleared out the .local/share/Trash folder.
no dice.

after some googling, I figured out that because I had selected "open with..." on a folder, and told Dolphin to "remember for future", it had the side-effect of changing the default action for folders from dolphin to that thing (which in this case was kid3).
So I changed it back from the "default applications" config panel. Now I can open the "trash:/ folder from Dolphin or from the desktop.

I think the trash:/ icon should always open with dolphin since other file browsers don't recignize those custom URLs.

But now I have a different problem. It is less major, if the trash works now.
I just deleted an item. Trash icon reports it is empty, even after logging out and logging back into KDE,
and even after removing and re-adding the desktop trash icon. I open it, and I can see the deleted file in trash:/ as expected.