D'oh! It seems I forgot to enable the "Rotate Cube" plugin - starting with both plugins enabled works for me.
Enabling or disabling plugins while Unity is running seems to crash Compiz. This is true for at least "Desktop Cube", "Rotate Cube", "Negative", "Opacity", and "Opacity, Brightness, and Saturation". All crash with the same backtrace from above.
D'oh! It seems I forgot to enable the "Rotate Cube" plugin - starting with both plugins enabled works for me.
Enabling or disabling plugins while Unity is running seems to crash Compiz. This is true for at least "Desktop Cube", "Rotate Cube", "Negative", "Opacity", and "Opacity, Brightness, and Saturation". All crash with the same backtrace from above.