I got it several times already and again now.
mouseUp: event on: aNodeMorph
^^^^^^^^^^^^^^^^^^^ nil
| path cmdOrCtrl clickedTheCheckbox |
"No change if model is locked"
clickedTheCheckbox := self clicked: event inTheCheckboxOf: aNodeMorph.
self listModel okToChange ifFalse: [^self].
self listModel okToDiscardEdits ifFalse: [^ self].
cmdOrCtrl := self commandOrCrontrolKeyPressed: event.
path := (event shiftPressed and: [self isMultiple])
ifTrue: [self shiftSelectMorph: aNodeMorph]
ifFalse: [
self autoMultiSelection
ifTrue: [self selectedMorphList ifEmpty: [] ifNotEmpty: [:l | l last path collect: [:p | p complexContents]]]
ifFalse: [self selectMorph: aNodeMorph multiple: ((cmdOrCtrl and: [self isMultiple]) or: [self autoMultiSelection]) clickedTheCheckBox: clickedTheCheckbox ]].
self selectionUpdateFromViewWhile: [ | selHolder |
selHolder := self newSelectionHolderWithNodePath: path.
self listModel selection: selHolder].
clickedTheCheckbox ifFalse: [ self lastClickedMorph: aNodeMorph ].
self selectionChanged.