Hey Kirk,
Sorry to bug you so quickly after the release but I'm having a weird problem with 4.6. I've restarted both PM and my computer to no avail.
I've got a folder of 103 images I shot yesterday. PM won't let me "tag" any photo past the 37th when sorted by Capture Time (by pressing "T", Apple+ or using the menu). It will let me Color Class, Rate and edit IPTC without problems. Everything but tag. I tried viewing only Tagged in case they were being tagged but the check mark wasn't showing up but no luck.
--[Pause in writing while I play around some more.]--
Now this is weird. I opened the folder back up in 4.5.4 and a whole lot of photos were tagged (I went through and tried a bunch in 4.6 but it didn't appear to be working). I cleared the tags in 4.5, re-tagged different shots and then opened the folder in 4.6. It now recognized all the new tags from 4.5 and even let me tag the ones it wouldn't before.
So something was wrong in 4.6 that was fixed by opening the folder again in 4.5. Any thoughts? Thanks.