Bert Freudenberg uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-bf.1122.mcz

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

Name: Morphic-bf.1122
Author: bf
Time: 20 April 2016, 6:09:34.906493 pm
UUID: a3dac7ab-cefe-4c77-9a8f-2d45f7f0dd9e
Ancestors: Morphic-tfel.1121

Prevent DNU when keystroke event causes text editor to get closed (owner is nil)

=============== Diff against Morphic-tfel.1121 ===============

Item was changed:
  ----- Method: StringMorphEditor>>keyStroke: (in category 'event handling') -----
  keyStroke: evt
  	"This is hugely inefficient, but it seems to work, and it's unlikely it will ever need
  	to be any more efficient -- it's only intended to edit single-line strings."
  
  	| char priorEditor newSel |
  	(((char := evt keyCharacter) = Character enter) or: [(char = Character cr)
  			or: [char = $s and: [evt commandKeyPressed]]])
  				ifTrue: [owner doneWithEdits; acceptContents.
  	self flag: #arNote. "Probably unnecessary"
  						evt hand releaseKeyboardFocus.
  						^ self delete].
  	
  	(char = $l and: [evt commandKeyPressed]) ifTrue:   "cancel"
  		[owner cancelEdits.
  		evt hand releaseKeyboardFocus.
  		^ self delete].
  
  	super keyStroke: evt.
+ 	
+ 	owner ifNil: [^self].
  	owner interimContents: self contents asString.
  	newSel := self editor selectionInterval.
  
  	priorEditor := self editor.  "Save editor state"
  	self releaseParagraph.  "Release paragraph so it will grow with selection."
  	self paragraph.      "Re-instantiate to set new bounds"
  	self installEditorToReplace: priorEditor.  "restore editor state"
  	self editor selectFrom: newSel first to: newSel last.
  !