If you drag a large file out of the File-Roller window, it immediately starts
unarchiving it.  The UI becomes very unresponsive to detecting the end of the
drag-drop operation, and you may end up dropping the icon in the wrong place as
a result.  Also, pressing Esc before dropping the icon doesn't seem to stop the
unarchive operation, i.e. it can't be aborted until it's completed.  Probably
the unarchival should not start happening until the icon is dropped at its
destination.

Additionally, there is a much worse bug: If you drag an icon out of the
File-Roller window, and then decide you didn't want to do that (perhaps because
the "Extracting" window has popped up and is making it hard to drop the file
where you want), if you drag the file back into the file-roller window and
release the mouse, then it actually starts *adding* the partially-decompressed
file back into the archive!  This overwrites the file in the archive with a
truncated version, so part of the file is lost.

These problems would all be solved by:
(1) only decompressing when you actually know the drag-drop target;
(2) making a drag-drop from a File-Roller window onto itself a no-op, or at
least where the source and dest folders in the archive are the same (so if you
drag from one directory onto the icon of another directory in the same archive,
it should probably add the file to that directory, but not when source and dest
dirs are identical).