Exit Title/Close Window - problem if No is selected

Hello all, having a weird problem that I hope there is an easy solution to.

I have an Exit Title/Close Window action on a button, which works as it should when clicked in IE (we only support IE at our organization). The dialog box appears saying "The webpage you are viewing is trying to close the window. Do you want to close this window?". If Yes is clicked, then the window closes as expected. If No is clicked so that the user returns to the course window, they are no longer able to click or navigate in any way in the course. I have a bunch of other html courses that use exactly the same button, and they are all working just fine - no problem if No is selected, they can simply return to the course and keep working. What the heck is going on in this one? Oh, and of course, we have a meeting with our internal client this afternoon, so would love to have it fixed by then. So swift responses would be totally appreciated!! Thanks!