fixed categories cache invalidation for duplicated sprites

HISTORY.md

@@ -73,6 +73,7 @@
 ### 2021-12-10
 * Catalan and German translation updates, thanks, Joan!
 * translation support for the libraries list, thanks, Joan!
+* objects: fixed categories cache invalidation for duplicated sprites
 
 ### 2021-12-09
 * blocks, threads: never push untested last minute changes that might break everything

snap.html

@@ -18,7 +18,7 @@
         <script src="src/widgets.js?version=2021-17-09"></script>
         <script src="src/blocks.js?version=2021-12-09"></script>
         <script src="src/threads.js?version=2021-12-09"></script>
-        <script src="src/objects.js?version=2021-12-09"></script>
+        <script src="src/objects.js?version=2021-12-10"></script>
         <script src="src/scenes.js?version=2021-11-24"></script>
         <script src="src/gui.js?version=2021-12-10"></script>
         <script src="src/paint.js?version=2021-07-05"></script>

src/objects.js

@@ -87,7 +87,7 @@ BlockVisibilityDialogMorph*/
 
 /*jshint esversion: 6*/
 
-modules.objects = '2021-November-09';
+modules.objects = '2021-December-10';
 
 var SpriteMorph;
 var StageMorph;
@@ -1942,7 +1942,7 @@ SpriteMorph.prototype.fullCopy = function (forClone) {
     c.freqPlayer = null;
     c.primitivesCache = {};
     c.paletteCache = {};
-    c.categoriesCache = {};
+    c.categoriesCache = null;
     c.imageData = {};
     c.cachedColorDimensions = c.color[this.penColorModel]();
     arr = [];