1504941 - Customize Linux scrollbar appearance in Dark Theme only

Status: RESOLVED WONTFIX

(DevTools :: General, defect, P3)

Description

[Julian Descottes [:jdescottes]]

Attachment: scrollbars_linux_light_theme.png

Follow up to Bug 1471163.

In Bug 1471163 we started using the scrollbar-color property to create a dark theme scrollbar for Linux. However since scrollbar-color forces to use a fallback version of the scrollbar, we decided to also apply it to the light-theme, in order to have consistency between our themes.

https://searchfox.org/mozilla-central/rev/7c848ac7630df5baf1314b0c03e015683599efb9/devtools/client/themes/common.css#58

We have received feedback that the fallback scrollbars were perceived as a regression for light theme users (Bug 1471163 comment 17, Bug 1471163 comment 19, Bug 1471163 comment 21). The goal of this bug is to go back to native scrollbars for light theme for the moment. This requires discussions with UX before moving forward. 

Ultimately it would be great to be able to reuse the dark scrollbar of GTK themes that support it (Bug 1504787).

Comment 1

[Florens Verschelde :fvsch]

> The goal of this bug is to go back to native scrollbars for light theme for the moment.

I'm mostly against it, because if the user uses a dark GTK theme they will get dark/black scrollbars in the light theme.
See https://bug1471163.bmoattachments.org/attachment.cgi?id=9014444 (Rules scrollbar) for how that looks.

Comment 2

[Julian Descottes [:jdescottes]]

(In reply to Florens Verschelde [:fvsch] from comment #1)
> > The goal of this bug is to go back to native scrollbars for light theme for the moment.
> 
> I'm mostly against it, because if the user uses a dark GTK theme they will
> get dark/black scrollbars in the light theme.
> See https://bug1471163.bmoattachments.org/attachment.cgi?id=9014444 (Rules
> scrollbar) for how that looks.

As I said in the summary, happy to discuss this, I also don't know what is the best option. 

One thing to keep in mind is that the scenario you describe in your screenshot is the current situation with Firefox 63 or earlier. So this wouldn't be a regression. But the fact that light theme scrollbars are no longer GTK scrollbars can be seen as a regression. Is the consistency between light and dark themes scrollbars worth the regression?

Or there's also my suggestion of adding a linux-only setting to use default scrollbars.

Comment 3

[Brian Grinstead [:bgrins]]

IMO it'd be preferable to come up with a solution for the web platform implementation (which I guess is Bug 1504787) instead of special casing any particular OS / DevTools themes.

Comment 4

[Florens Verschelde :fvsch]

> But the fact that light theme scrollbars are no longer GTK scrollbars can be seen as a regression.

Agreed. I'm maybe coming around to keeping the GTK scrollbars for the light theme, with a fix we can land in beta. :P

Then if we get a better platform-level solution, we can update to that (which can end up as a regression for some users using GTK themes without light/dark subthemes, but at least we change our behavior only once).

> IMO it'd be preferable to come up with a solution for the web platform implementation (which I guess is Bug 1504787)

I think it might be bug 1492040 (for CSS `scrollbar-color:light|dark` keywords), provided we choose to implement it on Linux in a way that keeps the GTK theme.

Comment 5

[Florens Verschelde :fvsch]

Twitter post asking for user feedback:
https://twitter.com/FirefoxDevTools/status/1063062774400667649

Comment 6

[Florens Verschelde :fvsch]

User feedback for the non-native scrollbars is mixed, but mostly positive.
As a result we have decided to keep the recent changes in Beta/Nightly, and not treat them as a regression. So I'm going to close this bug.

We do have some users who prefer the native scrollbars, and we would like to re-enable them in the future. We will need to achieve a few things to be able to switch back to native scrollbars:

1. Ability to ask the OS for a "dark" or "light" look. (E.g. GTK themes can have "dark" and "light" subthemes.)
2. Good results in both GTK-based environments and KDE/Plasma (some of our users who strongly prefer the non-GTK scrollbars are KDE users).

Work on this topic should go in bug 1504787.