1652259 - Moving window from high DPI monitor to low DPI one sometimes adds white border

Status: RESOLVED FIXED

(Core :: Widget: Win32, defect, P3)

Description

[Kagami Rosylight [:saschanaz] (they/them)]

0. Prepare two monitors with their DPI different, and set the lower DPI one as the main monitor.
1. Move your Firefox window to the higher monitor
2. Maximize the window.
3. Restore down the window
4. Move it the lower monitor

Expected: No white border
Actual: It appears. Maximizing again removes it.

This doesn't happen without Step 2. I'm not sure why it matters.

Comment 1

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

Set release status flags based on info from the regressing bug 1483448

Comment 2

[(No longer employed by Mozilla) Aaron Klotz]

Are you looking into this?

Comment 3

[Kagami Rosylight [:saschanaz] (they/them)]

I'm currently working on a DOM bug, but I can try again after that. Do you want to take a look?

Comment 4

[(No longer employed by Mozilla) Aaron Klotz]

Too busy at the moment, just wondering.

Comment 5

[[:philipp]]

we're also seeing a couple of reports from users with those white borders on sumo & reddit, who have set firefox to run in windows 7 compatibility mode.

Comment 6

[Kagami Rosylight [:saschanaz] (they/them)]

Attachment: Bug 1652259 - Update client margins when DPI changes r=cmartin

Currently margin values only change when the window goes fullscreen, causes unexpected white borders when moving to a lower-DPI display. This patch fixes that by updating the values whenever DPI changes.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4b99cd59c105
Update client margins when DPI changes r=aklotz

Comment 8

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/4b99cd59c105