Christoph Thiede uploaded a new version of System to project The Trunk:
http://source.squeak.org/trunk/System-ct.1280.mcz

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

Name: System-ct.1280
Author: ct
Time: 10 January 2022, 11:03:03.429359 pm
UUID: fa106a43-6333-374a-aa71-53ab31792e69
Ancestors: System-ct.1279

Honors preference #checkForUnsavedProjects when closing a project.

=============== Diff against System-ct.1279 ===============

Item was changed:
  ----- Method: Project>>okToChange (in category 'release') -----
  okToChange
  	"Answer whether the window in which the project is housed can be dismissed -- which is destructive. We never clobber a project without confirmation"
  
  	| answer |
  	(self isCurrentProject and: [self isTopProject]) ifTrue: [
  		self inform: 'You cannot close the top project.'.
  		^ false].
  	
+ 	((Preferences valueOfFlag: #checkForUnsavedProjects) ==>
+ 		[self confirm: ('Do you really want to delete the project\{1}\and all its content?' withCRs translated format:{self name})])
- 	(self confirm: ('Do you really want to delete the project\{1}\and all its content?' withCRs translated format:{self name}))
  		ifFalse: [^ false].
  
  	self subProjects ifNotEmpty: [:sp |
  		answer := Project uiManager
  			chooseFrom: #(
  				"1" 'Lift all sub-projects'
  				"2" 'Discard all sub-projects (NO UNDO!!)'
  				"3 or 0" 'Cancel')
  			lines: #(2)
  			title: ('The project {1}\contains {2} sub-project(s).' withCRs translated format:{self name. sp size}).
  		
  		(answer = 0 or: [answer = 3]) ifTrue: [^ false].
  		answer = 1 ifTrue: [self liftSubProjects. ^ true].
  		answer = 2 ifTrue: [^ sp allSatisfy: [:ea | 
  				[ea okToChange] valueSuppressingMessages: {'*delete the project*and all its content*'}]]].
  	
  	^ true!