migrated a toggle button label variant

snap.html

@@ -41,7 +41,7 @@
                     null,
                     null,
                     () => world.isDevMode = !world.isDevMode,
-                    'dev mode',
+                    new SymbolMorph('gears'), //'dev mode',
                     () => world.isDevMode,
                     null,
                     'hacker possibilities'

src/widgets.js

@@ -863,7 +863,8 @@ ToggleButtonMorph.prototype.createLabel = function () {
                         this.labelShadowOffset : none;
                 this.label.shadowColor = this.labelShadowColor;
                 this.label.color = this.labelColor;
-                this.label.drawNew();
+                this.label.fixLayout();
+                this.label.rerender();
             }
         } else if (this.labelString instanceof Morph) {
             this.label = this.labelString.fullCopy();