[juzfoo]

always struggle trying anything related to drag n drop on my ubuntu 12.10, because the moment i drag a file on nautilus the entire sets of apps get disabled on my unity sidebar except firefox and nautilus. and even firefox doesn't open so basically am stuck :(

[ZeroGravitas]

You can use the window pinning (not sure of the right word) to quickly move a window to take half the screen by dragging it to either side. Then you can do the same with the the other window. Once done dragging to the top will fullscreen it again.

[enyo]

Dropzone also supports click to upload, so you do not HAVE to drag'n'drop. It's just cooler if you can ;)