Chris Muller uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-cmm.1778.mcz

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

Name: Morphic-cmm.1778
Author: cmm
Time: 23 August 2021, 5:10:22.507528 pm
UUID: 17be2087-83c6-465d-9055-bb0c37b5ff62
Ancestors: Morphic-mt.1777

Make cloning an Explorer window a UI operation only, don't clone the underlying domain object.

=============== Diff against Morphic-mt.1777 ===============

Item was changed:
  Model subclass: #AbstractHierarchicalList
+ 	instanceVariableNames: 'currentSelection'
- 	instanceVariableNames: 'currentSelection myBrowser'
  	classVariableNames: ''
  	poolDictionaries: ''
  	category: 'Morphic-Explorer'!
  
  !AbstractHierarchicalList commentStamp: '<historical>' prior: 0!
  Contributed by Bob Arning as part of the ObjectExplorer package.
  !

Item was added:
+ ----- Method: AbstractHierarchicalList>>veryDeepInner: (in category 'copying') -----
+ veryDeepInner: aDeepCopier
+ 	"This method required to avoid copying my 'currentSelection'.  See Object>>#veryDeepCopyWith:."
+ 	super veryDeepInner: aDeepCopier!