I can not say I noticed this myself, and have used Firefox 5 for quite a while, (Nightly & Aurora channels). I have however noted quite a few comments that may be about this or similar problems. (Or I could be making a correlation that is not valid)

I do have XP myself, and a few versions of Firefox installed, but have not been able to reproduce the problem. Possibly it only affects wide screens or certain display resolutions, (I am using 1024 x 768).

• What display resolution are you using ?
• Exactly what is lost, and sides or top ?
• What does it affect, does it occur with blank pages, or only certain websites
• Maybe you could add a screenshot from
  • firefox 4
  • and firefox 5 so everyone can see what is happening.

You may find answers in one of the other threads, so from quickly scrolling a few pages I have come across the following:

• the left side of the screen cannot be seen
  I suggested trying zooming and the scroll bars
• only half the page is showing unless i go into fullscreen mode
• The rigt side {right side} of the window is cut such that I cannot access things on that side even after trying to resize it still cannot.
• the veiw {view} on my screen has shifted to the right
• how do i see the whole page? the wording is cut off at the right. how do i center the page?
• i cant exit full screen i tried F11 and F12 nothing worked on my dell laptop!!! GRRR
• I wish arrow keys to scroll the entire page. Now they act like Notepad.
  (possibly a caret browsing [F7] problem)
• and some older ones with recent posts
  • how do i change the zoom or size of my entire e-mail

darren86 has posted that apparently conflicting add-ons may cause the problem, but seems unsure which Add-on in particular.

Note the general troubleshooting advice is

• try safe mode but in the first dialogue window you see with a list of options do NOT make changes just click on continue
  • if you disable and re-enable addons and have a lot of them try disabling all, then enable 1/2, if no problem enable 1/2 of the others (ie 1/4); such methods are quicker than enabling or disabling one at a time.
• basic troubleshooting
  • or the more comprehensive http://kb.mozillazine.org/Standard_diagnostic_%28Firefox%29
• for plugins try checking with http://www.mozilla.com/en-US/plugincheck/

Note also updating add-ons may help, and it could in-fact be some plugin rather than an add-on causing the problem.

I've gone through disabling all the plug-ins and extension I had on my browser. By loading them methodically i've found that the one causing the problem was in the Extensions category:-

Babylon Toolbar 1.1.8.

By not loading this my original problem as reported at the top has gone away and Firefox is displaying pages correctly within the boundaries of the screen display.

Problem solved.

Thanks for your replies and help.

Cheers

Stephen

Thanks for the update, others are now also reporting this problem is related to use of the Babylon toolbar.

I have had a similar, however somewhat different, thing happen. Just starting today, my FF browser (7.0.1) loads up in Full Size (maximize) screen, however it will not allow me to make the browser window smaller. It will not show up the arrows on the side or the corners to size down, and when I hit the button in the right upper corner so that it can scale down it - instead - minimizes to the computer's toolbar. I had the babylon toolbar installed about a week ago and then uninstalled it so it's no longer installed.

Hi WilowRaven,

Maybe you are just in full screen view mode, try using keyboard key F11 that toggles full screen on and off. If that does not work it may be better to start your own question about your problem.