This little page demonstrates a little bug with IE 10 (consumer preview version 10.0.8250.0 (x64)): it seems when a rotateZ transform is applied, setting the opacity to 0 will correctly animate the object but once it is finished, the object appears, as if opacity was set back to 1 (although the developer tools correctly shows it's 0)

Try clicking on the three elements: the opacity is supposed to be set to 0.

This DIV has no transformation

Click-me to set opacity to 0
This DIV has rotateZ(-10deg) transform applied

Click-me to set opacity to 0
This DIV has scale(.9) transform applied

Click-me to set opacity to 0