Cursor shadow not displaying (but might still be there?)

I noticed that my cursor sometimes displays with a shadow (e.g. over a Firefox window) and sometimes without (e.g. over a Nautilus window, or a title bar).

I took screenshots to try and show the difference but noticed that apparently there is a shadow when over a Nautilus window - but it's not displayed on screen (unless Shutter inserts a cursor image). Compare the screengrabs of Firefox and Nautilus here: [IMG]http://ubuntuforums.org/attachment.php?attachmentid=218067&stc=1&d=1337176946[/IMG][IMG]http://ubuntuforums.org/attachment.php?attachmentid=218068&stc=1&d=1337176946[/IMG] with a camera shot of Nautilus: [IMG]http://ubuntuforums.org/attachment.php?attachmentid=218070&stc=1&d=1337176946[/IMG][IMG]http://ubuntuforums.org/attachment.php?attachmentid=218069&stc=1&d=1337176946[/IMG]

My first thought is that this could be Compiz as the shadow vanishes when I move over the window titlebar. However, both Resize and Move cursors have shadow.

Does anyone have any ideas where to look next?

This may be the same issue I am experiencing. The icons (for example files ) on desktop do not have shadows in their names. Thus the names are invisible on white background. This is a GTK or Nautilus issue. I am using Gnome-shell DE.