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Firefox Developer Edition starts up at a fixed position and size

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I am running Firefox Developer Edition (123.0b1) on Windows 11 and every time I start Firefox it maximises and then resizes to a set size with the maximise button set to restore size mode (I.e. the window thinks it is maximised). I have followed the steps detailed for this question: https://support.mozilla.org/en-US/questions/1411093 however that does not resolve my issue. This has only started recently after I turned the laptop into a tablet and back again. Once I "restore" the window and then I maximise the window it works as expected. However it is very annoying. Also if I start another instance of Firefox this new instance does not exhibit the same behavior.


Computer: HP Envy OS: Windows 11 with all current updates and as far as I can tell AI is turned off using a group policy.

I am running Firefox Developer Edition (123.0b1) on Windows 11 and every time I start Firefox it maximises and then resizes to a set size with the maximise button set to restore size mode (I.e. the window thinks it is maximised). I have followed the steps detailed for this question: https://support.mozilla.org/en-US/questions/1411093 however that does not resolve my issue. This has only started recently after I turned the laptop into a tablet and back again. Once I "restore" the window and then I maximise the window it works as expected. However it is very annoying. Also if I start another instance of Firefox this new instance does not exhibit the same behavior. Computer: HP Envy OS: Windows 11 with all current updates and as far as I can tell AI is turned off using a group policy.

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Try deleting the xulstore.json file in your profile folder.

You can also install an extension like Maximize All Windows (on Startup).