1825474 - Firefox window shown with border when using multiple displays with different DPIs

Status: UNCONFIRMED

(Core :: Graphics: WebRender, defect, P2)

Description

[Václav Nováček]

Attachment: ff_border.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/112.0

Steps to reproduce:

I have following display setup (from left) with corresponding DPIs...

• 15" laptop 3840x2160 250%
• 24" display 1920x1080 100% (main display)
• 24" display 1920x1080 150%
  Windows 10 with light theme, FF 112b8 with dark theme

Actual results:

When Firefox is started it looks fine, no border visible, once it's minimized and restored again it has thick white border. Maximalization and restore of the window removes the border temporary.
Thickness of the border depends on which display is shown. It's ok on laptop, no border at all, on main display is most wider and on second 24" display is bit thiner.
Worth to mention that the top border is there as well, but window icon/tab bar covers it. Top border area for window resizing is much thicker then, the resize cursor is shown down to a half of the tab icons, those can be switched from the bottom half below.

Expected results:

Firefox window shall have no border on any display. It should appear always the same.

Comment 1

[Václav Nováček]

Update: Once laptop is closed - its display dissapears, FF behaves correctly. No border is shown on both displays when it's minimized and restored.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Graphics' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:bhood, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 4

[Bob Hood [:bhood]]

Václav, can you please attach your about:support output?

Also, is it possible that you can test this same behavior using another browser (Chrome or Edge) and see if it is specifically FF that does this?

Comment 5

[Václav Nováček]

Attachment: about-support.json

Comment 6

[Václav Nováček]

I havn't noticed that behaviour using any other apps (including Chrome and Edge), only Firefox does it. about:support report attached.

Comment 7

[Václav Nováček]

Attachment: about-support-clean.json

Comment 8

[Václav Nováček]

Attachment: ff_border-demo.gif

Comment 9

[Václav Nováček]

Any progress here, do you need more info?