This is a limitation to the close event because that is a kendo event. But I suggest you do your validation in the dialog where you have a save and cancel button events. But the limitation then is when the user clickes the x button in the top-right corner... But there are ways to deal with that e.g. rootscope dirty flag.

I ended up doing validation on the save button in the dialog, did not need to trigger validation on cancel or X button!

Fixed