1927038 - Poor contrast for the active tab in vertical tabs sidebar, especially with dark mode styling

Status: RESOLVED WORKSFORME

(Firefox :: Tabbed Browser, defect, P1)

Description

[Jeff Fortin]

Attachment: Screenshot with dark mode on GNOME 46 on Fedora 40 (Linux)

The new vertical tabs sidebar (activated through about:config with sidebar.verticalTabs = True) is nice, but unlike horizontal tabs which have a different background color behind them, the sidebar has the same background color for the tabs and the background behind them, which makes it very difficult to spot the active tab, because there is only the shadow outline, no contrast of background colors.

This is particularly evident in dark mode (tested on GNOME), as shown with the screenhsot above.

Comment 1

[Dão Gottwald [:dao]]

This was supposed to be fixed by bug 1915862 in version 132 (which went to release today), I think. Gijs, can you confirm? Jeff, what version of Firefox are you on?

Comment 2

[:Gijs (he/him)]

(In reply to Dão Gottwald [:dao] from comment #1)

This was supposed to be fixed by bug 1915862 in version 132 (which went to release today), I think. Gijs, can you confirm?

That changed pinned tabs and some of the hover/active states. The changes in that bug were at https://searchfox.org/mozilla-central/rev/a547d790fa7facb8d0addb9197797dc52b31e8f2/browser/themes/shared/browser-colors.css#99 and the light/dark themes, but that rule is only applied if we're not using native-theme which I guess we set on Linux?

So it looks like on Linux this is set to color-mix(in srgb, -moz-dialog 85%, white). That's the toolbar bgcolor (via https://searchfox.org/mozilla-central/rev/a547d790fa7facb8d0addb9197797dc52b31e8f2/browser/themes/shared/tabbrowser/tabs.css#35 ). Which conveniently is also the sidebar background colour.

So I think this just needs addressing separately for Linux. :-\

Comment 3

[Sam Foster [:sfoster] (he/him)]

I think this should be fixed. As of bug 1928151, we're now using the same background color for the sidebar as the horizontal toolbars in this scenario - when we're using the system theme. That's going to be the OS' theme's ActiveCaption color for the not-selected vertical tabs (they are transparent, we just see whatever the sidebar background color is) contrasted with color-mix(in srgb, -moz-dialog 85%, white) for the selected tabs in dark mode.

So its technically possible to end up with very similar colors I guess? But seems much less likely now. However, we do hard-code some very specific color values for e.g. the Adwaita theme which might mean this issue is obscured for most of our testing which does tend to be Ubuntu with its default theme. So can you confirm if you are still able to reproduce this on today's nightly Jeff?

Comment 4

[Sam Foster [:sfoster] (he/him)]

Attachment: bug-1927038-fedora-gnome-vertical-tabs.png

This is using Nightly 134.0a1 buildID 20241119094105, dark mode in Fedora 41. This looks like it was fixed.

Comment 5

[Sam Foster [:sfoster] (he/him)]

Reporter, I'll leave the need-info in case you want to confirm this is fixed for you too. I don't have mozregression set up in this environment so I can't easily confirm which patch fixed it.