This is from my work desk, so I'm trying my best, but won't be around the program for another few days most likely-
but I'm trying to help.
I think it'll go like this:
You should be able to do it fairly quickly, by opening the menu editor, doing a few things-
Create a form titled something like 'showfps', and define it with the 'float GetFPS()' function.
Now open your .lay file that's appropriate, (likely fps.lay)
and create layout box option to call up the 'showfps' form you just created in the spot you
specify in the .lay file..
This **should** work, and should be quick and easy. The menu editor is pretty impressive.
Helpful areas in the doc's:
http://www.gamecore3d.com/docs/user-guide/scripting/menu-scriptinghttp://www.gamecore3d.com/docs/user-guide/menu-gui/modal-dialogshttp://www.gamecore3d.com/docs/scripting-reference/gui/CreateControlhttp://www.gamecore3d.com/docs/scripting-reference/gui/ShowForm