Bug Do not fail on empty url. This should not append on modern browsers.

mindplot/src/main/javascript/widget/LinkEditor.js

@@ -92,7 +92,9 @@ mindplot.widget.LinkEditor = new Class({
             event.stopPropagation();
             event.preventDefault();
 
+            if (input.value != null && input.value.trim() != "") {
                 model.setValue(input.value);
+            }
             this.close();
         }.bind(this));
 
@@ -139,5 +141,4 @@ mindplot.widget.LinkEditor = new Class({
     show:function () {
         this.open();
     }
-
 });