To fix this for your situation is not simple. You will need to recreate the button class used in kooljs.js (I assume you are using the CreateJS export libraries). There is a hit area bug in the current version which will be corrected in the next version to be released in about 10-14 days but that bug is probably not responsible for what you are seeing. You might need a custom hit area shape for each button or maybe clone the up state shape for the hit area shape. If you like, I can send you the button class in javascript. Make your own button class and use it instead but it would mean editing the exported html5 but not to a great extent. Where it says "new Btn", you would replace it with something like "new MyBtn". If you want the button class, email me.