I think this would be a very useful feature to add.
This looks very nice!
My little request is...
The word order "Move to" "category" does not suit some languages such as Japanese, etc. Could you make any good language-independent UI?
Thanks in advance.
As Hiroto says, in Japanese the "Move to" is a bit difficult to put into Japanese, since it would more naturally come after the category with something sort of like "<< move" ("ni idou").
However I guess it could (and in other parts of Moodle perhaps is) achieved with something like, "move to the following category." It would be very difficult to design GUIS to meet all the languages that Moodle now supports.