Hi,

If Raise or lower windows is selected in Tools (Alt + T) > Options > Content > Advanced (beside Enable Javascript), you can try disabling it.

As a test you can also try closing all open sites in the first window, exit Firefox, delete the sessionstore.js file in the Firefox Profile Folder after exiting Firefox and check. To open the profile folder via Firefox: Help (Alt + H) > Troubleshooting Information > Show Folder.

Firefox Profile Folder & Files

If you applied any Windows tweaks/programs you may have to make adjustments in the external Windows program's settings.

You can also Reset Firefox and check if it's a Firefox specific phenomenon.

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Are there any tabs open in that other window that might have refreshed or do you have extensions installed that may display information that has changed?

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

• Do not click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode

Thanks for all the ideas. Unfortunately none of them made any difference. This has only been happening (IIRC) since the 16.0.0 update.

I seem to be progressively losing all sorts of things in Firefox as time goes on - double-click stopped selecting the word under the cursor ages ago, as did Alt-click activating 1-Click Answers. Does that give anyone any ideas?  :-)

Thanks cor-el, it does seem to only happen with Add-Ons enabled, so now to find which one... (I don't use tabs, BTW.)

It still does it with all Add-ons manually disabled, or in safe mode, but not consistently - it'll misbehave three times in a row in the same scenario, then after closing all browser windows and restarting, it won't. Grrr.

Try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

• https://hacks.mozilla.org/2010/09/hardware-acceleration/

Disabling hardware acceleration didn't make a difference, though in testing it I did find a way to reliably reproduce the problem.

If I shut down all FF windows and open this page from a link and Ctrl+N, the new window appears then this one jumps to the top as if I'd done Alt+Tab. But from then on I can Ctrl+N and the new windows stay on top. Does that give anyone any clues?  :-)