Firefox window doesn't snap on first window opening

### Microsoft PowerToys version

v0.96.1

### Installation method

Microsoft Store

### Area(s) with issue?

FancyZones Editor

### Steps to reproduce

So far this appears to be a bug with Firefox application but I feel there have been others. I have checked firefox and I do not have picture in picture enable.

The issue is that when I first open a window for Firefox browser, it snaps over into place but then resizes itself immediately to be slightly in from the top of the screen and around 10 pixels in from either the left or right hand side of the screen ( dependining on which zone I last had it in).

If I already have a window open with Firefox any subsequent windows will correctly snap to a zone.

If I close the windows and immediately reopen then (as in no system restart) it will default back to being unsnapped.

Any thoughts for what I can try? I've tried playing with FanzyZones options by ticking deselecting and selecting all the options but the behaviour does not work as it does with other applications.

Thanks

### ✔️ Expected Behavior

Window to snap into place on first opening of firefox

### ❌ Actual Behavior

Win 11 Home
533509
English
User install
Running as admin

### Additional Information

_No response_

### Other Software

Firefox version 147.0.1 (64-bit)

[PowerToysReport_2026-01-17-20-20-06.zip](https://github.com/user-attachments/files/24691832/PowerToysReport_2026-01-17-20-20-06.zip)

Start by reproducing the first-window behavior in FancyZones Editor with Firefox 147.0.1 on Windows 11, using the listed steps and the attached PowerToys report as context. Compare the first Firefox window with subsequent windows and verify that the window snaps fully into the selected zone after the fix.

Written by the indexing model from the issue text.