Marcel Taeumel uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-mt.1431.mcz

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

Name: Morphic-mt.1431
Author: mt
Time: 15 May 2018, 6:28:31.290184 pm
UUID: 5d3be43c-b155-8547-93f7-23d355c228be
Ancestors: Morphic-kfr.1430

Fixes a regression with "aBorderedMorph borderColor: nil"... which used to work fine... ;-)

=============== Diff against Morphic-kfr.1430 ===============

Item was changed:
  ----- Method: BorderedMorph>>borderStyle: (in category 'accessing') -----
  borderStyle: aBorderStyle 
  
  	super borderStyle: aBorderStyle.
  
  	self flag: #compatibility. "mt: For older code, update the instance variables. Should be removed in the future."
+ 	borderWidth := self borderStyle width.
+ 	borderColor := self borderStyle color.!
- 	borderWidth := aBorderStyle width.
- 	borderColor := aBorderStyle color.!