The player overview panel is divided into three parts - top, middle, and bottom.
If you locate the bottom part (line 568), there are two containers ("L" and "R"), so you have to edit the horizontal_layout="-1,1,-1" to allow another container and copy/paste the same container it's already here.
The bottom part of the code can look like this:
Just delete that part and set the width.
<!-- Condition -->
<record id="PcOI" width="30"/>
That's part of the default graphic/paper. You have to edit the appearance of the paper.xml itself for all things within these folders.
graphics/boxes/custom/interface/tab bar - background
graphics/tabs/standard/normal/top- buttons