Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences in the address bar and press enter.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences in the address bar and press enter

Select Advanced > General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

Does that page have a fixed background image?

safe mode,disable hardware acceleration,disable smooth scrolling,deleting cache and deleting cookies. didn't help

the site does not have a background image (white bg)

Can you post a link to a publicly accessible page (i.e. no authentication or signing on required)?

You can test for issues with background images by temporarily disabling website colors.

• Tools > Options > Content : Fonts & Colors > Colors : [] "Allow pages to choose their own colors, instead of my selections above"

unfortunately, this does not happen on the front page (the public part) only on the actual RSS feed (which requires registration)

Did you try Safe Mode and disable website colors like I suggested above?

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox