1429398 - Scrolling down with keyboard no longer works correctly in at least Firefox

Status: RESOLVED FIXED

(bugzilla.mozilla.org :: General, defect, P1)

Description

[Boris Zbarsky [:bzbarsky]]

STEPS TO REPRODUCE:

1)  Start Firefox 57.
2)  Load https://bugzilla.mozilla.org/show_bug.cgi?id=1419771
3)  Make the window narrow enough that a horizontal scrollbar appears
    (see bug 1429290).
4)  Try to scroll down via the page-down key, or hitting space while having the
    focus on the viewport.

EXPECTED RESULTS: Scrolling works.

ACTUAL RESULTS: Scrolling does not work.  Needless to say, this is super-annoying. Multi-finger gestures to go-to-end and whatnot also do not work correctly, which makes getting to the comment textarea a huge pain. 

As soon as I make the window wide enough that the horizontal scrolbar disappears, scrolling starts to work again.

I haven't dug into the exact styles involved, but certainly this rule:

    @media screen and (min-width: 1024px) {
        #wrapper {
            overflow: hidden;
            width: 100%;
            height: 100%;
        }
    }

is what makes the scrolling work in a wider window.  If I turn off that "height: 100%" in inspector, I get an extra scrollbar inside the viewport scrollbars (just like I have with a narrower window) and scrolling stops working correctly.

Please either stop assuming that windows are more than 1024px wide, or at least test on windows that are narrower than that.

Comment 1

[:glob ✱]

this does the trick for me in my user-style for bmo:

#wrapper {
    height: 100%;
}

Comment 2

[Boris Zbarsky [:bzbarsky]]

Fwiw, I generally try to avoid user styles because I want to be testing our product the way most users experience it (and because I am not happy with the performance profiles I see with things like stylish).

Comment 3

[Dylan Hardison [:dylan] (he/him)]

For this one, it seems that the media is just wrong. The author intended for it to disable the fixed navigation bar, but instead it just breaks keyboard scrolling. I'll revert the @media portion and have a push out in the next hour.

Comment 4

[Dylan Hardison [:dylan] (he/him)]

Attachment: PR

Sorry for the delay, in a meeting.

Comment 5

[Nathan Froyd [:froydnj]]

The initial STR are broken for me on https://bugzilla.mozilla.org/show_bug.cgi?id=1422734 in a window that is more than 1024px wide (1148px according to xwininfo).

Comment 6

[Dylan Hardison [:dylan] (he/him)]

(In reply to Nathan Froyd [:froydnj] from comment #5)
> The initial STR are broken for me on
> https://bugzilla.mozilla.org/show_bug.cgi?id=1422734 in a window that is
> more than 1024px wide (1148px according to xwininfo).

Scrolling with keyboard definitely doesn't work on very narrow windows. There's a fix in the PR,
pending tests. My hour has passed but we'll get it to out today. I'm also working on the unrelated issue of BMO comments being hard to read on narrow screens as well -- and kohei has a more long-term fix in mind for that.

Comment 7

[Dylan Hardison [:dylan] (he/him)]

Comment on attachment 8941450 [details] [review]
PR

patch actually from kohei, so r=dylan.