1269149 - rv46 scrollbar too narrow in Linux/KDE

Status: NEW

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

Description

[Felix Miata]

Attachment: screenshot of 20160421124000 on 120 DPI openSUSE/KDE3 desktop

Environments in which observed:
A.Fedora 24, KDE Plasma 5, 32 bit:
1-default DE theme (Breeze)
2-Oxygen (optional) DE theme
openSUSE 42.1, KDE3, oxygen-gtk DE theme, 64 bit
B.default FF theme

Actual behavior:
1a-scrollbutton-up and scrollbutton-down are missing (openSUSE/KDE)
1b-all buttons missing from scrollbar area (Fedora)
2-clicking above or below scroll grab button behaving as if shift key is held down, scrolling more the farther away from the scroll grab button the click is made
3-scrollbar so narrow it's hard to get mouse pointer to land on it

Expected behavior:
1-working scrollbuttons in their usual locations
2-clicking above or below scroll grab button without shift key held down scrolls only ~one screen per click
3-scrollbar width matches the rest of the DE

Comment 1

[Felix Miata]

Missing buttons looks like Bug 1268874 but default scrollbar width appears could or should be a separate theming issue.

Comment 2

[Rainer Bielefeld]

@reporter:
Only 1 problem / Bug report, <https://developer.mozilla.org/en-US/docs/Mozilla/QA/Bug_writing_guidelines#Open_a_new_bug_report_for_each_issue!>! Please limit this one for 1 of the problems and submit separate bug reports for the other problems.

a) For illustration of what problem is your screenshot?

Comment 3

[Rainer Bielefeld]

@Loic:
"Bug 1269145 - Scrollbar buttons missing" and "Bug 1269172 - Behaviors transposed for {Click on Scrollbar} and {Shift+click on Scrollbar}" probably also area "Bug 627699 - (gtk3) Port GTK2 to GTK3"?

Comment 4

[Felix Miata]

(In reply to Rainer Bielefeld from comment #2)
> a) For illustration of what problem is your screenshot?

It shows narrow current vertical scrollbar in rv46 compared to two previous FF releases (38esr and 10esr), to current SM release, and to native apps, which is Comment 0 item #3, as I've now changed summary to match: "rv46 scrollbar needlessly narrow in Linux/KDE". C0#1 is bug 1269145. C0#2 is bug 1269172.

Comment 5

[Felix Miata]

I still believe this remains as I filed it, primarily a theming issue, a toolkit issue only secondarily. And it's readily reproducible on multiple Linux versions using various non-Gnome DEs....

Comment 6

[Felix Miata]

Attachment: 132 DPI screenshot of FF 46 and 17esr on Mageia 5/KDE 4 desktop

KDE here is set to use Oxygen icon theme in GTK apps, which is what Firefox 17esr is using, along with Clearlooks GTK theme. KDE is set to use Adwaita for GTK3 apps, but with no other GTK3 apps installed, it's beyond me to discern whether Adwaita is having any impact at all on v46 appearance here.

The actual target width of scrollbars in recent Firefox versions may well be the same as in apps native to the environment, but it's their highlight color and contrast that control perceived width and its effect on usability. Compared to those in less recent FF versions (e.g. 38esr) and native apps, 46 scrollbars by default could and should be doing better than they are in these two attachments.

Comment 7

[Gérard Talbot]

Actual behavior:
3-scrollbar so narrow it's hard to get mouse pointer to land on it

Expected behavior:
3-scrollbar width matches the rest of the DE

I have recently distribution-upgraded from KDE 4.14.13 and Kubuntu (trusty) 14.04.5 LTS to KDE 4.14.22 Kubuntu (yakkety) 16.10 and *_several components_* of the Firefox 50+ interface are no longer resizable (or stretchable or user-settable) for accessibility purposes. Their fixed, rigid status hurt accessibility and negatively affect my ability to use Firefox. The scrollbar width is one of them.

Anything that requires more eye-mouse-hand fine motricity is going to hurt people over 50. I do not understand why Firefox does not use, does not rely on the desktop environment values of KDE theme.

Comment 8

[Gérard Talbot]

After more experiment and tweakings, I confirm that the scrollbar is too narrow and not resizable. It always used to be 15px by default (which was too narrow for me) but, at least, I was able to resize, to increase it size (eg under KDE 4.14.13 and Kubuntu 14.04). Now, I no longer can resize its width: that is anti-user-friendly to me.

- - - - - - -

Actual behavior:
2-clicking above or below scroll grab button behaving as if shift key is held down, scrolling more the farther away from the scroll grab button the click is made

Expected behavior:
2-clicking above or below scroll grab button without shift key held down scrolls only ~one screen per click

I confirm this. When I click above or below the scrollbar thumb in Chrome 56.0.2924.87, I scroll up or down 1 screen per click. 
With Firefox 51.0.1, not so: I reach the document area correspondent to the scrolling point. With Chrome 56, I would have to Shift+click to do the equivalent.

Comment 9

[Gérard Talbot]

Workaround
----------

1- Install the GTK3 theme clearlooks-phenix-7.0.1 
(System Settings –> Apparence of applications –> Style of applications GNOME(GTK) –> Select a GTK3 theme) : this works for me. Firefox 53.0.2 now uses larger, much more reasonable-thicker scrollbars (probably not overlay but classical) and now also with scrollbar arrows (<, >, ^, v).

2- if the scrollbar width is not large enough for you, then you may try (I have not tried this yet!) to set it at line 1333 of the file
.themes/clearlooks-phenix-7.0.1/gtk-3.0/gtk-widgets.css

line 1321: /**************
line 1321:  * Scrollbars *
line 1321:  **************/
(...)
line 1333:     -GtkRange-slider-width: 15; /* this value is most likely the one to modify */
line 1334:    -GtkRange-stepper-size: 15px;
line 1335:    -GtkScrollbar-min-slider-length: 30;
line 1336:    -GtkRange-stepper-spacing: 0;
line 1337:    -GtkRange-trough-under-steppers: 0;

Disclaimer: I have not tried yet to modify this value. I want to examine the code more...