Andreas Raab uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-ar.202.mcz

==================== Summary ====================

Name: Morphic-ar.202
Author: ar
Time: 6 October 2009, 12:55:02 pm
UUID: 3e090b46-4a28-e642-a6b2-e0b2d55962d9
Ancestors: Morphic-ar.201

Fix FileList to not blow up when attempting to set a nil directory (for example, when collapsing a selected tree).

=============== Diff against Morphic-ar.201 ===============

Item was changed:
  ----- Method: FileList>>setDirectoryTo: (in category 'directory tree') -----
  setDirectoryTo: dir
+ 	"Set the current directory shown in the FileList. 
+ 	Does not allow setting the directory to nil since this blows up in various places."
+ 	dir ifNil:[^self].
  	self directory: dir.
  	brevityState := #FileList.
  	self changed: #fileList.
  	self changed: #contents.
  	self changed: #pathAndPattern.!