So I was using AL and cleaning up the hierarchy -- moving things up and down, making new categories, etc. And due to my being a mouse spaz, I accidentally rested on "Delete Category" when I was shooting for "Add Category". POOF! My hard-won category vanished -- and took all the metadata with it. I had a lot of things living under the now-deleted category and I have to go through and rebuild them all. (And yes, I should be running regular backups but it wasn't happening...)
Unlike its neighbors "Add" and "Rename", "Delete Category" is destructive -- and there's no Undo that I can see. I think there should be a speed-bump, at least for idiots like me.
-=-Bernie
Guess you're using categories more than I do, so here's one AL version with delete confirmation Dialogs:
http://neocron.webspaceforme.net/library/installer/Advanced_Library_1_7_1_6.zip (//http://)