tweaked syntax element alpha handling

src/blocks.js

@@ -786,7 +786,7 @@ SyntaxElementMorph.prototype.unflash = function () {
 };
 
 SyntaxElementMorph.prototype.doWithAlpha = function (alpha, callback) {
-    var current = this.alpha;
+    var current = SyntaxElementMorph.prototype.alpha;
     SyntaxElementMorph.prototype.alpha = alpha;
     callback();
     SyntaxElementMorph.prototype.alpha = current;

src/gui.js

@@ -3124,7 +3124,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 'before it picks up an object',
             new Color(100, 0, 0)
         );
-        /*
+//        /*
         menu.addItem(
             "Block alpha...",
             () => {
@@ -3149,7 +3149,7 @@ IDE_Morph.prototype.settingsMenu = function () {
             'set the blocks\'\nalpha value',
             new Color(100, 0, 0)
         );
-        */
+//        */
     }
     menu.addItem(
         'Microphone resolution...',