Everything is really wonky. The list you see is actually some messed-up column ListView since you can't just add items with icons to a normal list. RPG Maker 2000/2003 overrode the drawing system to do it with normal lists and that's why the font is all messed up everywhere (not to mention I think it was made with Delphi).
You can use Import Folder to grab many resources at once for now but ctrl+selecting files in the file mangler might work later.