Is it possible for the MultiUpload to support automatically assigning common category(s) to all the files.
Currently this can be achieved if you add wikitext categories in the comments box. The category (or categories) are assigned to the files, but the text remains in the comment box.
There could be either a separate text box for entering the category, or can be added through the comment box.
With a small modification (hopefully), any category text in the comment box should be applied as category to the files and then removed from the comment box.
I hope this makes sense.