1743344 - MozWinGlass frame transparency doesn't work since ~92

Status: NEW

(Core :: Graphics, defect)

Description

[Shane Hughes [:aminomancer]]

The MozWinGlass style appearance's transparency stopped working a while ago. I just checked back on it and it still doesn't work. It produces a fully opaque black background instead of a glass appearance. The same is true for MozWinBorderlessGlass btw.

Steps:

• Open Firefox on Windows
• Open browser toolbox > style editor
• Make a new user sheet
• Paste this:

#main-window { background-color: transparent !important; appearance: -moz-win-glass !important; }
#navigator-toolbox { background: transparent !important; }
toolbar { background: none !important; }

Comment 1

[Andrew Osmond [:aosmond] (he/him)]

Are you able to mozregression this?

https://mozilla.github.io/mozregression/quickstart.html

Comment 2

[Shane Hughes [:aminomancer]]

I can. But do you know how to prevent it from loading your actual firefox profile? The last time I used it ~1 year ago, it somehow managed to load my real profile a couple times, which wrecked the profile's prefs or databases or something. I have avoided it since then

Comment 3

[Darkspirit]

By default, mozregression creates each time a temporary profile, but there are also clone (default and recommended), clone-first, reuse. Only if you configure "reuse" (which is not recommended) and set the profile path to your regular Firefox profile, it directly uses and changes it.
Just make a backup of C:\Users\<username>\AppData\Roaming\Firefox to be safe. That's where your profiles (about:profiles) are stored.

Comment 4

[Shane Hughes [:aminomancer]]

(In reply to Darkspirit from comment #3)

By default, mozregression creates each time a temporary profile, but there are also clone (default and recommended), clone-first, reuse. Only if you configure "reuse" (which is not recommended) and set the profile path to your regular Firefox profile, it directly uses and changes it.
Just make a backup of C:\Users\<username>\AppData\Roaming\Firefox to be safe. That's where your profiles (about:profiles) are stored.

Where are these settings? I don't see anything like that in mozregression-gui. There are only 7 options in the latest release as far as I can tell. I did not change any settings, and I did back up my profile.

Honestly not sure how to do this anyway, because the bug will not be visible on any recent build of firefox without custom stylesheets. Is there a way to load the temp profile with a userChrome.css file or something along those lines? I don't want to have to open the devtools and paste in MozWinGlass rules for every build it runs.

Comment 5

[Shane Hughes [:aminomancer]]

I guess maybe the problem I had before was due to using the GUI. I tried the CLI program and it worked fine, although I had to set it to use a single profile so I could control the CSS styles. Well I just tried going all the way back to version 59 and it didn't work in a single instance. But I and many others have memories of it working, so I'm a bit perplexed. You can also find numerous references to translucency "breaking" on r/FirefoxCSS beginning around the time the first proton changes made it to a release build. I seem to remember noticing it during 92 but I don't normally use this feature, and I think I remember someone saying it happened when they updated to 89. So I aimed for before that, and the actual glass appearance looked very different but translucency still did not work. After 89 it seems like you get a white background with a gray titlebar and like, windows 98-esque window control buttons. Before that, either a solid black or solid white background across the entire window frame, and actually extending horizontally like 5px beyond the window frame on either side. Kinda weird. But no transparency of any sort going all the way back to 2017-01-01 :/

Comment 6

[Jim Mathies [:jimm]]

Can you please post your about:support text?

Comment 7

[Shane Hughes [:aminomancer]]

Attachment: AboutSupport text

Comment 8

[Jeff Muizelaar [:jrmuizel]]

aminomancer, does it help if you set gfx.webrender.compositor=false and restart the browser?

Comment 9

[Jim Mathies [:jimm]]

This isn't high priority, but might be interesting to understand where this broke.

Comment 10

[Shane Hughes [:aminomancer]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #8)

aminomancer, does it help if you set gfx.webrender.compositor=false and restart the browser?

No, I tried a couple builds with a test profile with that pref set in user.js, 2021-01-01, 2020-01-01, and 2019-01-01. The background is still always either solid white or solid black.

Comment 11

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

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.