firefox,thunderbird: too skinny of scrollbars plus scrollbar boundary not showing

[rik-shaw]

There are 2 usability issues when using firefox or thunderbird regarding scrollbars, when compared to gnome apps like Nautlius (at least using Ubuntu 15.10, Gnome 3.16).

First, the Firefox scrollbars:

Second, the Nautilus scrollbars (using Arc Darker theme):

Here are the 2 problems:

1. The firefox gray scrollbar is maybe 2 pixels skinnier.
2. The firefox "scrollbar boundary" is not shown. What I mean is the line to the left that shows the user the edge of the scrollbar box. Without that they don't realize they have a few pixels of "grace" when trying to click exactly on that "too skinny gray bar".

I first reported this bug to arc-firefox-theme, but the issue is consistent with thunderbird (NOT using the arc-firefox-theme) and with firefox (using the arc-firefox-theme). So I think the bug is here with the Arc theme.

Thanks for the great theming (and icon) work! Here is the arc-firefox-theme issue: horst3180/arc-firefox-theme#38

[horst3180]

Fixed with ce704e5.