Collapse Stacks List in Application Browser

[Sannyasin Sivakatirswami]

Sometimes I have many stacks open...some of these have a lot of 
sub-stacks. It seems that substacks of a mainstack, are, by default, 
always listed in the AB, the small disclosure triangle reveals the card 
list for the main stack... but what i would like to be able to do would 
be to collapse the mainstack line in the list such that all its 
substacks disappear also. And could then be later revealed as needed.  
Can this be done?