Hi iancant,
Sorry you are having problems.

Clearing the cache and the cookies for a site may correct that for specific sites.
Try. Does it help ?

• Read this for instructions, and other ideas
  Websites look wrong or appear differently than they should

Clearly it is not something that is happening and you must have some deeper problem. 'edit
Clearly it is not something that is happening to everybody, and should not be happening , you must have some deeper problem.

1. Try using Firefox in safemode, does that prevent the issue ?
   (You may also have to disable plugins in addition to using safe mode )
   Diagnose Firefox issues using Troubleshoot Mode
   Disable or remove Add-ons_how-to-disable-plugins
2. If that helps you then need to work out whether it is an extension or hardware acceleration causing problems Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Please post back to say how you get on.

None of your suggested solutions work. On this page, for example, source html lines 423 and on ["Post a Reply'] is followed by a black square, a set of 3 vertical lines then "Common responses". Between the vertical lines there are links [bold, italic, numbered list and bulleted list] but they are NOT visible. The html continues with various options [languages etc] then goes to bottom-of-page boilerplate. I can see no correspondence between html and displayed material in this section. This kind of thing occurs on MANY websites which display correctly on IE but incorrectly on Firefox.

This is a real and significant problem, please address it.

The quickest way to fix this may be to just reset Firefox - Refresh Firefox - reset add-ons and settings.

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Give this a try and let me know how it goes.
Thanks,
Michael

I seems rather as if you have javascript disabled, or you have something that is blocking javascript.

On this page the the edit icons will disappear if javascript is off. I sometimes ask people if they can see those as a test to see if javascript is off.

Safe mode would disable extensions. Safe mode will not disable other programs that could block javascript what security related software, including firewalls and blockers do you use (scriptblockers, addblockers etc).

See also

• Websites look wrong or appear differently than they should_check-that-javascript-is-not-blocked
• Fix problems connecting to websites after updating Firefox
• How to let Firefox use the internet on your Windows computer

This is a real and significant problem, please address it. 

This is a forum where most are volunteers and fellow users of Firefox like yourself. In cases like this it is quite probably the issue will be something on your own machine and not a Firefox problem.

Interestingly there is a slightly similar problem in this thread

• Drop down menus don't work in any version of Firefox with no add-ons installed immediately after a clean install

Resetting Firefox appears to have cleared the problem. Thankyou very much, it was starting to drive me crazy.