Comment 6 for bug 227907

The ezoom plugin uses a hacky method to allow users to interact with transformed windows (doing this properly requires input redirection support from the X server, which it doesn't have yet). A consequence of this approach is the mouse cursor disappearing bug mentioned here. From a comment in the source code:

 * Hide the real cursor and draw our own where it would be when zoomed in.
 * This allows us to navigate with the mouse without constantly moving the
 * zoom area. This is fairly close to what we want in the end when input
 * redirection is available.
 *
 * This second method has one huge issue, which is bugged XFixes. After
 * hiding the cursor once with XFixes, some mouse cursors will simply be
 * invisible. The Firefox loading cursor being one of them.

http://gitweb.compiz-fusion.org/?p=fusion/plugins/ezoom;a=blob;f=ezoom.c;h=5749c17e2e1fbe907f9f64e922acea59fd8f5ab7;hb=eb651d03c6477c0e522c1fb85cacca0d17cde4ed