Prelight works fine on the right side, if the menu button is on the left. On the left side thinks work fine if there is only the menu button. But everything else screws up.
If the cursor is about the menu button, it seems that always the first button is drawn with prelight. A setup like:
  shade,stick:menu,minimize,maximize,close
has some really weird results. List of what happens when one moves the cursor above the button:

shade:
  The "icon" is prelit, but not the button border.

stick:
  Not sure, probably the same as "shade" (don't draw anything there right now)

menu:
  The button border of the "shade" button gets the prelight, but not its content. (content probably at the right place, but not sure as I currently just use the icon and don't modify the prelight)

minimize:
  Button border of the "menu" button, contents of the "minimize" button.

maximize:
  button border of both "menu" and "maximize" buttons, and contents of "maximize" button.

close:
  This is done correctly.