I'm actually using compiz (as my primary window manager) at the moment and the issue persists after both compiz --replace, gala --replace (i.e. under gala) and upon reboot. I don't think it's an issue with the compositor (not at my end at least) as compiz is able to apply transparency to slingshot (see screenshot).
P.S. I swear that there were other replies to this bug previously (including one specifically pointing out that transparency was applied to slingshot in the attached screenshot). Hmm...
I'm actually using compiz (as my primary window manager) at the moment and the issue persists after both compiz --replace, gala --replace (i.e. under gala) and upon reboot. I don't think it's an issue with the compositor (not at my end at least) as compiz is able to apply transparency to slingshot (see screenshot).
P.S. I swear that there were other replies to this bug previously (including one specifically pointing out that transparency was applied to slingshot in the attached screenshot). Hmm...