Your description is too ambiguous, but Status-4-Evar extension restores use of status bar functionality in the replacement add-ons bar, explicit directions in this page of mine. The arrangement of its parts is customizable.

Please mark "Solved" one answer that will best help others with a similar problem -- hope this was it.

You can make Firefox 7.0.1 look like Firefox 3.6.*, see numbered items 1-10 in the following topic Fix Firefox 4.0 toolbar user interface, problems (Make Firefox 4.0 thru 8.0, look like 3.6). Whether or not you make changes, you should be aware of what has changed and what you have to do to use changed or missing features.

• http://dmcritchie.mvps.org/firefox/firefox-problems.htm#fx4interface

The position is chosen to make sure that a link at the bottom to the page doesn't obscure that pop-up.
You can force a position at the left instead of the default right position that allows to read text at the start of the last line by placing the mouse at the bottom right corner.

Thanks everyone. The Status-4-Evar extension fixed it for me. Sorry that I wasn't very clear. To clarify further: when I put the mouse over a link in our web application, there is a very long url because of the values passed in the url string. Because Firefox wasn't displaying the full url text, I couldn't see the values being passed. In the past, this was OK, because the url string was truncated from the RHS, meaning that I could see most of the values. However, Firefox has now altered its display of the URL in the status bar such that the middle of the URL is chopped out & replaced with '...'. This meant that I couldn't see some of the values being passed in the URL.

Thanks once again for your help.