Christoph Thiede uploaded a new version of Morphic to project The Inbox:
http://source.squeak.org/inbox/Morphic-ct.2057.mcz

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

Name: Morphic-ct.2057
Author: ct
Time: 26 November 2022, 1:50:40.467518 pm
UUID: 0bc53b37-9fd5-9643-8be1-722f0c6fd475
Ancestors: Morphic-ct.2056

Prevents pluggable buttons without a menu from acting on yellow-click. Why did we never notice this earlier? Yellow-click is for menus only ...

=============== Diff against Morphic-ct.2056 ===============

Item was changed:
  ----- Method: PluggableButtonMorph>>mouseUp: (in category 'event handling') -----
  mouseUp: evt
  
+ 	evt yellowButtonChanged ifTrue: [^ super mouseUp: evt].
  	self updateFillStyle: evt.
  	(self containsPoint: evt cursorPoint)
  		ifTrue: [self performAction].!