Marcel Taeumel uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-mt.2003.mcz

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

Name: Morphic-mt.2003
Author: mt
Time: 9 June 2022, 11:17:38.89573 am
UUID: e53457f4-4e83-2c4b-9fea-f5bcc1143401
Ancestors: Morphic-mt.2002

Offer a fast-path for window dragging. Requires #systemWindowEmbedOK to be disabled. NOTE that this is enabled by default when launching the preference wizard.

See:
- http://lists.squeakfoundation.org/pipermail/squeak-dev/2022-June/220861.html
- http://lists.squeakfoundation.org/pipermail/squeak-dev/2022-June/220872.html
- http://lists.squeakfoundation.org/pipermail/squeak-dev/2022-June/220878.html

=============== Diff against Morphic-mt.2002 ===============

Item was changed:
  ----- Method: SystemWindow>>mouseEnterDragging: (in category 'events') -----
  mouseEnterDragging: evt
  	"unlock children for drop operations"
  	
+ 	self flag: #performance. "mt: There may be no need to change appearance if no widget wants the drop. As a trade-off, we avoid expensive visual updates if the user drags a system window and window-embedding in nested world morphs is not allowed."
+ 	(evt hand firstSubmorph isSystemWindow
+ 		and: [Preferences systemWindowEmbedOK not])
+ 			ifTrue: [^ self].
+ 
- 	self flag: #performance. "mt: There may be no need to change appearance if no widget wants the drop."
  	self isActive ifTrue: [self lookFocused].
  		
  	(self isActive not and: [evt hand hasSubmorphs]) ifTrue: [
  		self activate. "unlock contents for drop"
  		evt hand addMouseListener: self. "for drop completion on submorph"
  	].!