Support content editable (issue 113).

core/utils.js

@@ -241,7 +241,8 @@ Blockly.isTargetInput_ = function(e) {
   return e.target.type == 'textarea' || e.target.type == 'text' ||
          e.target.type == 'number' || e.target.type == 'email' ||
          e.target.type == 'password' || e.target.type == 'search' ||
-         e.target.type == 'tel' || e.target.type == 'url';
+         e.target.type == 'tel' || e.target.type == 'url' ||
+         e.target.isContentEditable;
 };
 
 /**