Ive taken a look at it, here is my conclusion:
1. Why do you need the checkbox, it has no use (correct me if im wrong).
2. The problem is, when you checked the checkbox, then the focus is on that, and it absorbs all input.
It can be fixed, by doing this(last event):
<img src="http://puu.sh/6OtEd.png" border="0" />