STR:

1. Open a video Picture-in-Picture window on Ubuntu 19.10 (X11).
2. Resize PiP window from any edge except the bottom-right corner (hold and drag larger and smaller several times).

Expected:

Window position does not change.

Actual:

The window moves to the top/left of screen while dragging, depending on the edge that is resized. Only the bottom-right corner keeps the window position fixed, however it flickers rapidly between a small window and the desired size.

In addition, at small sizes there is letterboxing (dark strips) on the left+right edges and at large sizes on the top+bottom edges which did not exist before the regressing bug.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=57f9a3f2c4069bef8166df880d0b4ad8c0e92c45&tochange=0a6d64975cfa90788adf7851053f48ef523babb7

Regressed by Bug 1617115.

Martin, could you please set the priority flag of this bug?

Yes, this is caused by aspect ratio setting.

Can you set widget.use-aspect-ratio to false (you need to create it as false) and try again?

Thanks.

Disabling the aspect ratio lock avoids the window moving by itself when resized.

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is P3 (Backlog,) indicating it has been triaged, the bug's Severity is being updated to S3 (normal.)