Enable to set border width (used to change window size)

[JLuc]

When the mouse pointer is on window border, it changes into a double arrow, and user can change width and height of the window.
Alas, border is only 1 pixel width ! Thus, it requires very carefull positioning of the mouse to be able to trigger that basic feature.
There are other ways to change windows size, but mouse-on-border is the most expected one... and should be obvious to perform.

As stated in http://ubuntuforums.org/showthread.php?t=1482247&p=10351090#post10351090, solution is to edit
/usr/share/themes/Ambiance/metacity-1/metacity-theme-1.xml (for 'Ambiance')
and to set the following values in frame_geometry_normal as desired:
  <distance name="left_width" value="3"/>
  <distance name="right_width" value="3"/>
  <distance name="bottom_height" value="3"/>

3 to 5 pixels make it sooooo much easier to change windows size !!

Please put this setting into the Unity Tweak tool.

[JLuc (jluc-q)]

Ubuntu bug for this 1px border width issue dates 2007 : https://bugs.launchpad.net/metacity/+bug/160311
( Metacity Window Manager : Resizing windows by grabbing window borders is difficult)

As of today, 619 people are worried with it and would benefit of a possible tweak.