Please describe the problem:
In many forums, when attempting to close a tab, a pop-up error message 'There are unsubmitted changes to form elements' appears, requiring you to close this first.

I believe this is typically in pages that allow you to comment on them directly (perhaps in AJAX), and has happened to me in reddit, and facebook, to name two.

Steps to reproduce:
1. go to www.reddit.com 
2. click on comment, or any article (you may need to register)
3. close tab - error message appears.


Actual results:
error popup as above appears. 

Expected results:
tab to close silently

Does this happen every time?
yes

Other information:
I know there is a workaround for this, using gconftool, but it is annoying. It could perhaps be made an option in preferences to not have this error message, or a tick box to not show the error again, or just made clearer.