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 windowOn the menu bar, click on the ToolsFirefoxEdit menu, and select Options...Preferences....
- Select the Advanced panel.
- Click on the Network tab
- Click to close the Options windowClick to close the Preferences windowClose the Preferences window.
Now that your cache is cleared, visit the website again to see if the problem is solved.