it uses the default black and white X mouse pointer no matter which cursor theme I choose, except when hovered over a few select windows :

• the whole of the Firefox window

and the light parts of the images below :

• Panel Weather Plugin

  

• the GIMP :

  

the default theme doesn't give a preview when I select it in the mouse properties either (not sure if it should)

what's different about the highlighted parts of those images, and the Firefox window that would make the cursor change?
This started around the time I installed 4.4RC2, but I uninstalled that fully before installing 4.4.0, and it's not made any difference...