You can try the
new version in the gallery - though we noticed a quirk with subsequent uploads when using FF3.5 - investigating.
v1.3.1 (ZCS 5.x only) added the new dragenter/drop to the previous dragdrop. (We may even consider using dragover/dragleave with dropEffect sometime to give visual feedback your over the zone.)
HTML5 drag and drop in Firefox 3.5 – 0xDECAFBAD