[gnome-control-center] mouse: center horizontally using halign property

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 6c677bb0e9ac6330dfde17cf0ff1c5154a04b2c3
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri Jul 8 00:54:16 2016 -0300

    mouse: center horizontally using halign property
    
    The Mouse & Touchpad panel has a horizontally centered
    list, which is centered pixel-counting the list width and
    hardcoded margins.
    
    This approach has various issues. It resizes the window
    needlessly when e.g. the font changes the size, dpi or
    family. This is specially visible when dealing with low
    resolution screens, where the hardcoded margins are too
    much to fit a 720x480 screen with the Large Font accessibility
    setting on.
    
    Fix that by removing the margins and setting the horizontal
    alignment of the list to center. Since the list itself doesn't
    expand to fill the available space, there won't be any user-
    visible changes except that the panel is now able to scale
    down.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768529

 panels/mouse/gnome-mouse-properties.ui |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/panels/mouse/gnome-mouse-properties.ui b/panels/mouse/gnome-mouse-properties.ui
index 40ef3a9..db058ec 100644
--- a/panels/mouse/gnome-mouse-properties.ui
+++ b/panels/mouse/gnome-mouse-properties.ui
@@ -26,8 +26,7 @@
       <object class="GtkBox" id="prefs_widget">
         <property name="visible">True</property>
         <property name="can_focus">False</property>
-        <property name="margin_start">134</property>
-        <property name="margin_end">134</property>
+        <property name="halign">center</property>
         <property name="margin_top">12</property>
         <property name="margin_bottom">12</property>
         <property name="orientation">vertical</property>