I had the same issue when I moved to C3. To solve this problem I did this:
1. Set Fullscreen-Scale to (OFF)
2. Insert (Browser)
3. Create an event on Browser Resize
4. Create an Action (Browser > Execute Javascript) set global variables to height/width as seen below.
Then, in the index.html I added this tiny function
<script type="text/javascript">
var browser_h = 0;
var browser_w = 0;
function browser_s() {
browser_w = Math.max(document.documentElement.clientWidth, window.innerWidth || 0);
browser_h = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);
}
browser_s()
</script>[/code:3rnf890w]
You now have, fullscreen that is cropped.