If you increase the height of the fast reply by one level, the button to decrease its height will not work. The button works fine on larger sizes, but the fast reply box cannot be brought back to the default height.

Post it in the Bug Tracker, on top of forum :D

Yeah I noticed this on IE 7 (was not sure if it was me or what so forgot to note it down) :)

Happens on firefox too

Is that a bug or does it have a set height where you cannot shorten it?

Post it in the Bug Tracker, on top of forum :D

Oh, didn't see that :P.

Is that a bug or does it have a set height where you cannot shorten it?

It's a bug, because the default height is smaller than the height that it can't be made shorter than.

I can confirm this bug. Happened to me too.