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Firefox stays on Window mode

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So every time I open Firefox, it starts at Windowed mode, not in full screen mode. Right clicking the shortcut to select maximized in the Run section does not work for me. I would have to double click the top bar every time to get it to be full screen.

So every time I open Firefox, it starts at Windowed mode, not in full screen mode. Right clicking the shortcut to select maximized in the Run section does not work for me. I would have to double click the top bar every time to get it to be full screen.

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I have same problem. When I open Firefox it opens as a small window in the upper left of my screen, and then the second small window opens that is the one to enter the Firefox password. When I click the second window, it does let me enter the password. And I also have to do clicking on the small window to get it to go to full screen or to enter the password. If I have other apps open, the Firefox window almost gets hidden.

Currently running Windows 11 as of mid-December and Firefox version 96.0.1, and the problem seems to have started after the Win 11 update.

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https://support.mozilla.org/en-US/kb/changes-toolbars-and-window-sizes-are-not-saved You may have corrupt xulstore.json file.

Open your file browser to this hidden location:

  • Mac: *~/Library/Application Support/Firefox/Profiles
  • Linux: *~/.mozilla/firefox/Profiles
  • Windows: %AppData%\Mozilla\Firefox\Profiles
  • *C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles
  • Windows XP: C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\

Close Firefox. Search for the above file. Then rename or delete it. Restart Firefox.

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This does not solve the problem. Maybe for others it does but not for mine. I did what you said and it still didn't work for me. Refreshing Firefox does not help either.

Modified by user158825061702048981161559993040890724972

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Sauceman64 said

So every time I open Firefox, it starts at Windowed mode, not in full screen mode. Right clicking the shortcut to select maximized in the Run section does not work for me. I would have to double click the top bar every time to get it to be full screen.

Did you enable the privacy.resistFingerprinting setting in about:config? It modifies window dimensions as one of its "blend in with the crowd" changes. I've been ignoring threads about this particular behavior, so I don't know whether there is a quick fix.