Tested with:

Release 94
Beta 95
Nightly 96.0a1 (2021-12-02)

Tested on:

Windows 7
Windows 10

Steps:

1. Launch Firefox and go to youtube.com.
2. Play a random video.
3. Enable PiP.
4. Resize the PiP window to the min-value.
5. Resize the PiP window to normal or any random size.

Actual result:

There are extra black spaces in the left and right sides of the PiP window.

Expected result:

The PiP window should be resized accordingly to any dimension.

Regression range:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=d745c21f3ff22be1c0530a77114c12b6ac3e9c40&tochange=fbdb6c91bd6256415a54c5198fb1e3bff8dd7c64

Set release status flags based on info from the regressing bug 1681098

I am able to reproduce this issue on a Windows 10 VM (unable to for MacOS or Ubuntu).

Set release status flags based on info from the regressing bug 1681098

NI from Michelle since they are the assignee of the regressing bug. Could you please look into this? Thanks!

Will forward the NI since I don't know much about PiP's workings and mconley helped me with the patch on the regressing bug whenever mconley has their NI's unblocked

Forwarding the NI as I mentioned