Thanks for sharing this great plugin! I like it!
I found out, that
is undefined until you open the menu. So there's an error in your destroy-method.
I simply changed it to
The error occured when I closed a tab which contains a GridPanel with your plugin and I didn't open the menu at least once.
_destroy : function()
if (this.colMenu.el) this.colMenu.el.remove();
(But it's reproducable in a simple example. I modified the array-grid example and added your plugin. Then I called grid.destroy() on a button click. Just the same error.)
Maybe the problem occurs in your app as well and you can apply the little change to your code.
Keep up the great work!