It seems like with Firefox’s tab overflow features that were released in Firefox 2, people either love it, hate it or want to change it. Now I have had several E-mails sent to me looking for the best way to get at least two of those done of those done. (Not really sure if I could help you love it.) Luckily for you and me I have found a guide that will help you do just that.
Some folks, including myself do not like the tab overflow feature that was added to Firefox 2. For those of you who are not familiar with this feature when the width (in pixels) of the tabs becomes less than set amount (default is 100 pixels) Firefox will add scroll buttons to each end of the tab bar (see sample here). The purpose of this feature was so that all the tabs open will have a minimum width of 100 pixels. At 100 pixels the tabs are still relatively readable.