Default to making speech bubbles persisnt until clicked

src/blocks.js

@@ -2158,7 +2158,7 @@ SyntaxElementMorph.prototype.showBubble = function (value, exportPic, target) {
         txt,
         img,
         morphToShow,
-        isClickable = false,
+        isClickable = true,
         ide = this.parentThatIsA(IDE_Morph) || target.parentThatIsA(IDE_Morph),
         anchor = this,
         pos = this.rightCenter().add(new Point(2, 0)),