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I get a double blue bar at the top of the browser window which makes certain commands fail.

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When I open a second application of FireFox a double blue line appears at the top of its browser window. To close the window you must use the top most X. When in this state you can only view one destination page as you can not move back to a previous page you just viewed. How do I restore its normal (single blue bar) state?

When I open a second application of FireFox a double blue line appears at the top of its browser window. To close the window you must use the top most X. When in this state you can only view one destination page as you can not move back to a previous page you just viewed. How do I restore its normal (single blue bar) state?

Chosen solution

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


In Firefox 4 and later Safe mode disables extensions and disables hardware acceleration.

  • Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

If disabling hardware acceleration works then check if there is an update available for your graphics display driver.

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All Replies (2)

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Chosen Solution

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


In Firefox 4 and later Safe mode disables extensions and disables hardware acceleration.

  • Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

If disabling hardware acceleration works then check if there is an update available for your graphics display driver.

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Thanks cor-el,

In response to your first reply I followed all your directions and found it was the Xmarks 4.0.2 add-on. When disabled I no longer had the problem.

I tried updating Xmarks 4.0.2 and the problem persisted. I went through each of the Options for the Xmarks and removed each of the settings one-by-one and found it still to have the problem. Only way was/is to disable Xmarks.

Thanks for your help. It was very much right on!

Have a great day.