1197590 - middlemouse.scrollbarPosition no longer works on GTK3 scrollbars

Status: NEW

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

Description

[Kestrel]

Ubuntu 15.04

Steps to reproduce:

1. middlemouse.scrollbarPosition = true
2. Click the middle mouse button on a scrollable scrollbar.

Expected result:

Scrollbar should instantly jump to clicked position like with GTK2 scrollbars.

Actual result:

Nothing happens. 

It seems that left-clicking on the scrollbar now achieves the same result so this preference might be unnecessary.

Comment 1

[Lee Salzman [:lsalzman]]

It looks like this behavior is "intentional" at least in our code, as observed here:

https://dxr.mozilla.org/mozilla-central/source/layout/xul/nsSliderFrame.cpp?from=ShouldScrollForEvent#1061

GetScrollToClick() is internally checking the "gtk-primary-button-warps-slider" setting, which defaults to true. If this happens to be true, and hence as observed the primary button handles scroll-to-click, then the middle mouse button scroll-to-click gets disabled.

Karl, is this expected behavior? Did gtk2 not default this to true before?

Comment 2

[Karl Tomlinson (:karlt)]

Looks like the default value may have changed in GTK+ 3.6.

https://developer.gnome.org/gtk2/2.24/GtkSettings.html#GtkSettings--gtk-primary-button-warps-slider
https://developer.gnome.org/gtk3/3.16/GtkSettings.html#GtkSettings--gtk-primary-button-warps-slider

Following the system behavior is intended for default pref values.

How that is meant to work with prefs is tricky when prefs don't have a use-system option.

Comment 3

[flying sheep]

> It seems that left-clicking on the scrollbar now achieves the same result so this preference might be unnecessary.

actually that’s important for desktop integration.

all my applications jump with middle mouse, i want to be able to configure firefox to do the same, especially if it always had that pref. simply make the pref toggle that property and set it to whatever you want per default, but still let us change it

Comment 4

[Jim Rees]

It took me a while to figure out how to fix the gtk setting. Create the file ~/.config/gtk-3.0/settings.ini if you don't already have one, and put this in it:

[Settings]
gtk-primary-button-warps-slider = false

Comment 6

[Jeffery Small]

Thanks to Jim Rees for a usable workaround!  Also agree that this should be handled internally within Firefox by honoring middlemouse.scrollbarPosition.

Comment 7

[Jeffery Small]

Firefox 46.0
Xubuntu 15.10

Another issue that I notice that may be related to GTK+ is that cut and paste withing Firefox has become very unreliable.  I have a dual desktop system with two versions (two different profiles) running on each.  The above workaround by Jim Reese has been implemented.  The usual Linux ability to select text using B1 and then past it elsewhere using B2 works between apps on either screen, but does not work between a selection made on one screen and the Firefox instance running on the other.

Examples:

1: I B1 select text in an xterm and can B2 paste it into another another xterm or into the URL bar on Firefox running on either screen.

2: I B1 select text from the Firefox URL bar and can B2 paste it into another app (xterm for example) on the same screen, but cannot paste it into any app, including Firefox, on the other screen.

So B1/B2 copy/paste are working system-wide as expected, but Firefox is doing something strange with its own selections that do not conform to expected behavior.

Comment 9

[Russ Pridemore]

Yes, thank-you for the work-around.  I'm not sure if my criticism should be against firefox or gtk, but if a left mouse click causes the view to jump to that location, how is the user supposed to page down or up with the mouse?

Comment 11

[BugBot [:suhaib / :marco/ :calixte]]

The severity field for this bug is relatively low, S3. However, the bug has 3 duplicates.
:stransky, could you consider increasing the bug severity?

For more information, please visit auto_nag documentation.

Comment 12

[BugBot (nomail) [:suhaib / :marco/ :calixte]]

The last needinfo from me was triggered in error by recent activity on the bug. I'm clearing the needinfo since this is a very old bug and I don't know if it's still relevant.

Comment 13

[Nathan Teodosio :nteodosio]

If we take only the setting description https://kb.mozillazine.org/Middlemouse.scrollbarPosition in consideration:

True
Center the scroll position on the location of the middle click. (Default for Linux/Unix.)

False
Do nothing. (Default for all but Linux/Unix.)

Then this is still relevant because if the GTK3 option gtk-primary-button-warps-slider is True (which is the default), then the middle-click does nothing regardless of the value of middlemouse.scrollbarPosition.

Arguably Firefox' default behavior should match the behavior of other GTK3 applications in the system.