Old version cached
Firefox caches websites, which means it saves some files on your machine so that it doesn't have to re-download everything when you visit sites. If a website has updated their code, Firefox may still be using some of the old code along with some of the new, which can make a web page display incorrectly. To fix this, you need to clear the cache:
- At the top of the Firefox window , click on the Tools menu, and select Options... .
- Select the Advanced panel.
- Click on the Network tab
- Click
- Click to close the Options window to close the Preferences window .
Now that your cache is cleared, visit the website again to see if the problem is solved.