Attached Link: http://market.renderosity.com/mod/forumpro/showthread.php?thread_id=2642738#message_2651056

The new editor is adding several IFRAMES to the page, which is what's causing the problem with the back button (they're being added to the history) [Mozilla 1.7.12].

This is causing much more trouble for others, see attached link.

Edit to add :
It's an editor bug. The default sample show this problem.