The Inbox: Morphic-ct.1589.mcz

A new version of Morphic was added to project The Inbox:
http://source.squeak.org/inbox/Morphic-ct.1589.mcz

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

Name: Morphic-ct.1589
Author: ct
Time: 15 November 2019, 2:23:59.326144 pm
UUID: 3d155fd4-4bef-6140-802c-2be39c9e40ff
Ancestors: Morphic-mt.1587

Make TransformMorph more robust against empty submorphs

Steps to reproduce a concrete related issue:
1. PluggableTreeMorph new openInWorld
2. Focus it
3. Press Escape

=============== Diff against Morphic-mt.1587 ===============

Item was changed:
  ----- Method: TransformMorph>>numberOfItemsPotentiallyInView (in category 'geometry') -----
  numberOfItemsPotentiallyInView
  "Answer the number of items that could potentially be viewed in full,
  computed as my visible height divided by the average height of my submorphs.
  Ignore visibility of submorphs."
 
+ | localSubmorphBounds |
+ localSubmorphBounds := self localSubmorphBounds.
+ localSubmorphBounds ifNil: [^ 0].
+ submorphs ifEmpty: [^ 0].
+ ^ self innerBounds height // (localSubmorphBounds height / submorphs size)!
- ^ self localSubmorphBounds
- ifNil: [0]
- ifNotNil: [:lsBounds |
- self innerBounds height // (lsBounds height / submorphs size)]!