That is probably caused by an add-on. From the searching I've done, it might be the Trackmenot add-on. If you close Firefox, then start Firefox in Safe Mode, does the problem still occur? To start in Safe Mode, go to Help > Restart with Add-ons Disabled.

If the problem does not occur in Safe Mode, then you can disable your extensions one-by-one until you find out which one is causing the problem. See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.

my friend i donot use that addon i use these foll link text

Did you try Save mode ?

• Help > Restart with Add-ons Disabled

See also this thread: [/questions/921535]

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

If it does work in Safe-mode then disable all extensions and then try to find which is causing it by enabling one at a time until the problem reappears.

• Use "Disable all add-ons" on the Safe mode start window to disable all extensions.
• Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Hi cybervibin,
It doesn't have to be that extension. It might be another. If you follow the instructions at Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems, it should help you find out which one.

If you have any trouble with those instructions, just tell us and we'll walk you through it.