1 files changed, 5 insertions, 2 deletions
diff --git a/objects.js b/objects.js
index 3d6b0e5..7a51455 100644
--- a/objects.js
+++ b/objects.js
@@ -1466,8 +1466,11 @@ SpriteMorph.prototype.appearIn = function (ide) {
 // SpriteMorph versioning
 
 SpriteMorph.prototype.setName = function (string) {
-    this.name = string || this.name;
-    this.version = Date.now();
+    if (string != 'mouse-pointer' && string != 'pen trails'
+            && string != 'edge') { // used by system
+        this.name = string || this.name;
+        this.version = Date.now();
+    }
 };
 
 // SpriteMorph rendering