A new version of Morphic was added to project The Inbox:
http://source.squeak.org/inbox/Morphic-LM.1678.mcz

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

Name: Morphic-LM.1678
Author: LM
Time: 3 September 2020, 12:58:35.620287 pm
UUID: d1262531-fd1c-43a1-ba41-9ff8b3728a3a
Ancestors: Morphic-ct.1677

Prevent users from creating multiple SystemProgressMorphs by abusing uniqueInstance.

Currently the UniqueInstance class variable is not set properly when it is nil, which allows the user to call it multiple times to generate many SystemProgressMorphs, defeating the purpose of having a *unique* instance.

=============== Diff against Morphic-ct.1677 ===============

Item was changed:
  ----- Method: SystemProgressMorph class>>uniqueInstance (in category 'instance creation') -----
  uniqueInstance
+ 
+ 	^ UniqueInstance ifNil: [UniqueInstance := super new]!
- 	^UniqueInstance ifNil:[super new]!