Problem: You're running some schnazzy Ubuntu and you want your cursor to point to the right because you use your mouse with your left hand, so then you go download something like this lefthanded version of the Obsidian cursor and install it using the official cursor selection program (not gcursor, since it doesn't seem to actually do anything when you click the buttons), and now the cursor shows up when you're hovering over firefox, but when you go outside the window or onto the desktop it reverts to that annoying old default cursor!

Solution: Log out, and as you log back in, select the 'Ubuntu (no effects)' desktop.

This solved the cursor problem for me.

Stupid Linux. >:(