For the buttons border search for this element and replace it for the following line:
<element id="Controls.DropdownButton.Default" bg="Ground+4" bg2="Ground" fg="Default" bdr="Ground-2" />
Add this <element id="MenuButton.Border" bg="Ground-2" /> for the menu button border.
I like that flatter look using white ground+ variables. I will flat the main gui in a future version
