URLbar and Back/Forward regression Rated 2 out of 5 stars

This Extension is NOT exactly ready for prime time. I found that, while it does format the current HTTP page location consistent with MS-Internet Explorer 7-up when it is running correctly, all too often it shuts down the Back and Forward buttons, and even occasionally it shuts down the Location text field. This will make the UI difficult to handle for those not used to selecting Back, Forward and Home from the menu(s).

This review is for a previous version of the add-on (4.3). 

Hi, what do you mean by 'shuts down'
smart text have no effect on Back and Forward buttons at all
most likely cause of what you see is incompatibility with other extension or, incompatible version of firefox
please use support site or e-mail, to find why smart-text doesn't work for you.