interactive button or menu activation
setmenu(button [,nsub])
setmenu(gwin,button [,nsub])
:button a character string. The button name : :gwin integer. The number of graphic window where the button is
installed
:
The function allows the user to make active buttons or menus created by addmenu in the main or graphics windows command panels.
`addmenu`_('foo') // New button made in main scilab window
`unsetmenu`_('foo') // button foo cannot be activated (grey string)
setmenu('foo') // button foo can be activated (black string)