Nicolas Cellier uploaded a new version of MorphicExtras to project The Trunk:
http://source.squeak.org/trunk/MorphicExtras-nice.288.mcz

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

Name: MorphicExtras-nice.288
Author: nice
Time: 13 April 2021, 4:42:17.42642 pm
UUID: 433930ea-23a3-bf42-839b-0f6b1251fc9e
Ancestors: MorphicExtras-eem.287

Fixup URLMorph: there is no instance of Symbol, Symbol is an abstract class for a few years now (15 years ?). We must test someObject isSymbol rather than someObject class == Symbol (or ~~ Symbol like here).

While at it, prefer isSymbol to isKindOf: Symbol.

=============== Diff against MorphicExtras-eem.287 ===============

Item was changed:
  ----- Method: PostscriptCanvas>>drawPolygon:color:borderWidth:borderColor: (in category 'drawing-polygons') -----
  drawPolygon: vertices color: aColor borderWidth: bw borderColor: bc 
  	| fillC |
  	fillC := self shadowColor ifNil:[aColor].
  	self
  		preserveStateDuring: [:pc | pc
  			 outlinePolygon: vertices;
  				 setLinewidth: bw;
  				
  				fill: fillC
+ 				andStroke: (bc isSymbol
- 				andStroke: ((bc isKindOf: Symbol)
  						ifTrue: [Color gray]
  						ifFalse: [bc])]!

Item was changed:
  ----- Method: PostscriptCanvas>>stroke: (in category 'private') -----
  stroke: strokeColor 
  	strokeColor ifNil: [^self].
+ 	strokeColor isSymbol
- 	(strokeColor isKindOf: Symbol) 
  		ifTrue: [^self paint: Color gray operation: #stroke	"punt"].
  	strokeColor isSolidFill 
  		ifTrue: [^self paint: strokeColor asColor operation: #stroke].
  	self preserveStateDuring: 
  			[:inner | 
  			inner
  				strokepath;
  				fill: strokeColor]!

Item was changed:
  ----- Method: URLMorph>>mouseUp: (in category 'event handling') -----
  mouseUp: evt
  	| pg ow newPage mm bookUrl bk |
  	"If url of a book, open it to that page, or bring it in and open to that page."
  	book ifNotNil: [book == false ifFalse: [
  		(bookUrl := book) isString ifFalse: [
  			bookUrl := (SqueakPage stemUrl: url), '.bo'].
+ 		(bk := BookMorph isInWorld: self world withUrl: bookUrl) isSymbol
+ 			ifFalse: [^ bk goToPageUrl: url].
- 		(bk := BookMorph isInWorld: self world withUrl: bookUrl) class ~~ Symbol 
- 			ifTrue: [^ bk goToPageUrl: url].
  		bk == #conflict ifTrue: [
  			^ self inform: 'This book is already open in some other project'].
  		(bk := BookMorph new fromURL: bookUrl) ifNil: [^ self].
  		bk goToPageUrl: url.	"turn to the page"
  		^ HandMorph attach: bk]].
  
  	"If inside a SqueakPage, replace it!!"
  	pg := self enclosingPage.
  	pg ifNotNil: [
  		(ow := pg contentsMorph owner) ifNotNil: [
  			pg contentsMorph delete.	"from its owner"
  			newPage := SqueakPageCache atURL: url.
  			mm := newPage fetchContents.
  			mm ifNotNil: [ow addMorph: mm.
  				page := newPage].
  			^ self]].
  	"If I am a project, jump  -- not done yet"
  
  	"For now, just put new page on the hand"
  	newPage := SqueakPageCache atURL: url.
  	mm := newPage fetchInformIfError.
  	mm ifNotNil: [self primaryHand attachMorph: mm.
  		page := newPage].
  
  !