In Xul, Within A Transparent Window, How Do I Hide The Mouse Cursor?

I have a Xul window that is transparent, and I need to hide the mouse cursor after 1 second. Applying cursor: none will not work, the mouse cursor still shows up in the transparent

Solution 1:

Your OS generally won't even bother to send mouse events to a completely transparent (area of your) window; as far as it's concerned, your window isn't there. However if your OS allows it, a nearly transparent window might work.