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How do I make new Firefox windows appear on my primary monitor as a default?

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  • Last reply by dannyc207

dannyc207
dannyc207
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I use a laptop. When I can, I hook-up a large monitor to be my primary view, and the laptop monitor becomes the secondary/extension screen. For some reason, Firefox constantly opens a new window on my laptop screen instead of on the large monitor in front of me. It didn't do this when I started using Firefox. But—perhaps because I moved the window to my laptop screen at one time—new windows now only open on the laptop screen. I've tried quitting Firefox with one window on the large screen, hoping that starting Firefox next time would open on the last monitor used, but that doesn't work. What do I have to do so new windows default to the large monitor?

I use a laptop. When I can, I hook-up a large monitor to be my primary view, and the laptop monitor becomes the secondary/extension screen. For some reason, Firefox constantly opens a new window on my laptop screen instead of on the large monitor in front of me. It didn't do this when I started using Firefox. But—perhaps because I moved the window to my laptop screen at one time—new windows now only open on the laptop screen. I've tried quitting Firefox with one window on the large screen, hoping that starting Firefox next time would open on the last monitor used, but that doesn't work. What do I have to do so new windows default to the large monitor?

Modified by dannyc207

Chosen solution

I don't think that it is possible to set what monitor to use for opening a new window.

Try to rename/remove xulstore.json and if present delete localstore.rdf in the Firefox profile folder with Firefox closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:preferences page.

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All Replies (5)

WestEnd
WestEnd
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That would be a O/S controlled based on what is determines is the main Windows screen. You will have to look at a windows forum for help on this.

dannyc207
dannyc207 Question owner
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When you say "main Windows screen" and "a windows forum", do you mean Microsoft Windows? I work with MacOS so Windows doesn't apply to me.

In addition, other browsers and apps open my primary monitor just fine. They seem to know which it is; how do I make Firefox know it?

cor-el
cor-el
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  • Top 10 Contributor
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Chosen Solution

I don't think that it is possible to set what monitor to use for opening a new window.

Try to rename/remove xulstore.json and if present delete localstore.rdf in the Firefox profile folder with Firefox closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:preferences page.

dannyc207
dannyc207 Question owner
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Thanks @cor-el! Removing xulstore.json did the trick. I hope this will be long-lasting and not some fluke of a fluke. At least I know this solution for next time.

dannyc207
dannyc207 Question owner
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UPDATE. Certainly didn't take long for this to go wrong again. I have a YouTube video playing in a Firefox window. I move the window to my laptop screen (the secondary monitor) so I can work on a project on my primary monitor. A few minutes later, I activate a new Firefox window and it appears on the secondary monitor. I close that window, move the one with the YouTube video to my primary monitor, and make a new Firefox window. It ends up on the secondary monitor.

I test a number of conditions that involve placing the Firefox window and restarting the app, and the results are the same: all new Firefox windows end up on the secondary monitor. I resort to removing xulstore.json and trashing it. This fixes the issue; new screens again open on my primary monitor.

But the mystery now is why do new Firefox windows end up defaulting to my secondary monitor? What's the trigger? Is this some kind of "feature" that's gone awry? I'm glad I have a remedy, but it's short term until there's a reason and solution to make new Firefox windows open on my primary monitor where I want them.