This morning I added a few pictures to Quick Collection and didn't have any problems. This afternoon, no matter what picture I pick, I get the following error if I try to add it to a Quick Collection:
"An internal error has occured: ?:0: attempt to compare two nil values"
I get this error message if I try to click the little quick collection "circle" in the top-right corner of the image. I also get it if I right-click on the image and select "Add to Quick Collection" from the popup menu.
Again, worked fine in the morning, but this afternoon not so much. Of course nothing's changed or has been upgraded in a few hours.
I tried closing and restarting the computer and that didn't help. I tried optimizing the catalog and that didn't help.