Tree/Titlepane height problem when you click during open/close

[guest]

the height effect, (when you click on a div and this div slowly change it's height to 0) if called more that 1 time before the effect complete (2 click in a very short time) have a bug, seems that before starting the effect it save the real height of the div, probably for rollback the second time, but if the div is in the effect it can have a different height, so the 2nd click would lost the original div's height, overwriting, i notice this bug in the treeview and in titlepane.

[bill]

Basically a dup/consequence of #2944, so we'll address it after that bug is fixed.

[dante]

dup of #2343

[bill]

(In [9498]) Make slideIn()/slideOut() assume a natural height for the node, rather than trying to obey a height specification on the node's style. This simplification fixes #2944, #2343, #3152