pq06021.st  ABRREMOVEALL: CAUSES DEBUGGER ON SORTEDCOLLECTION	

When we attempt to remove a collection of objects from a                       
SortedCollection using the abrRemoveAll: method, we get a debugger. 
This problem is unique to abrRemoveAll: as removeAll: works fine.  However, 
removeAll: doesn't post the events needed to automatically keep the visual
parts in sync. Also, if the collection to be removed only contains on object, 
the bug does not happen. 

File in pq06021.st to fix this problem.