Marcel Taeumel uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-mt.867.mcz

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

Name: Morphic-mt.867
Author: mt
Time: 13 April 2015, 5:16:16.01 pm
UUID: 52e544de-d33f-0346-9646-bfe830d53ac5
Ancestors: Morphic-mt.866

Fixed a bug with scrolling that occured at the transition from needing to not needing scrollbars (or vice versa). We must ensure that scroll bars reflect the current of the scroller---regardless of their visibility.

=============== Diff against Morphic-mt.866 ===============

Item was changed:
  ----- Method: ScrollPane>>extent: (in category 'geometry') -----
  extent: newExtent
  	
  	| oldW oldH wasHShowing wasVShowing noVPlease noHPlease minH minW |
  	
  	oldW := self width.
  	oldH := self height.
  	wasHShowing := self hIsScrollbarShowing.
  	wasVShowing := self vIsScrollbarShowing.
  
  	"Figure out the minimum width and height for this pane so that scrollbars will appear"
  	noVPlease := self valueOfProperty: #noVScrollBarPlease ifAbsent: [false]. 
  	noHPlease := self valueOfProperty: #noHScrollBarPlease ifAbsent: [false]. 
  	minH := self scrollBarThickness + 16.
  	minW := self scrollBarThickness + 20.
  	noVPlease ifTrue:[ 
  		noHPlease
  			ifTrue:[minH := 1. minW := 1 ]
  			ifFalse:[minH := self scrollBarThickness ].
  	] ifFalse:[
  		noHPlease
  			ifTrue:[minH := self scrollBarThickness + 5].
  	].
  	super extent: (newExtent max: (minW at minH)).
  
  	"Now reset widget sizes"
  	self resizeScrollBars; resizeScroller; hideOrShowScrollBars.
  	
  	"Now resetScrollDeltas where appropriate, first the vScrollBar..."
+ 	self height ~~ oldH ifTrue: [self vSetScrollDelta].
- 	((self height ~~ oldH) or: [ wasHShowing ~~ self hIsScrollbarShowing]) ifTrue:
- 		[(retractableScrollBar or: [ self vIsScrollbarShowing ]) ifTrue:
- 			[ self vSetScrollDelta ]].
  			
  	"...then the hScrollBar"
+ 	self width ~~ oldW ifTrue: [self hSetScrollDelta].
- 	((self width ~~ oldW) or: [wasVShowing ~~ self vIsScrollbarShowing]) ifTrue:
- 		[(retractableScrollBar or: [ self hIsScrollbarShowing ]) ifTrue:
- 			[ self hSetScrollDelta ]].
  
  !