I posted this in the general help under another thread, but I thought I should also bring it up here.
The UF client currently doesn't handle clickies correctly. After casting an inventory click item, it greys out the spellbar for the usual 2 seconds. Normally, spells can be cast from the spellbar immediately after the inventory click item is done casting.
I'm not sure if this affects any other clients other than UF - don't have any others to test on.