Firefox extension popup is way bigger than Chrome

Has anyone else noticed this? On Firefox the Bitwarden popup is noticeably larger than the same popup in Chrome, side by side on the same machine. I’m seeing it on:

  • macOS with the display set to “More Space” scaling

  • Windows 11 on a 1440p monitor at default scaling

It’s not browser zoom, extension popups ignore that. And it’s not just font size, the whole popup is bigger: width, padding, icons, everything. On a smaller laptop screen the popup ends up taking a chunk of the viewport.

I poked at the code and I think it comes down to how Firefox resolves CSS pixels against the backing scale factor for extension popups vs how Chrome does it. Page-side content looks identical between the two browsers. It’s specifically the popup chrome.

Throwing this out there to see:

  1. Is this just my setup, or are other folks seeing it too?

  2. Is there a workaround I’m missing in settings?

  3. Would the team be open to a fix that scales the popup down on Firefox + HiDPI? I put together a small patch that does this (linked below if anyone wants to try it or pick it apart). It shrinks the popup about 20% only when devicePixelRatio > 1 and the browser is Firefox, so standard-DPI users aren’t affected.

PR: https://github.com/bitwarden/clients/pull/20852

Screenshots of before/after are in the PR. Curious if I’m alone here or if this resonates.

Hi, Victor… I’m not seeing it on my machine.

I have two displays:

  1. Built-in: 2880x1800 laptop screen, at 125% scale
  2. Secondary: 3840x2160 external monitor at 100% scale

On both machines, the BW pop-ups appear to be the same size. …cheers!