new g_hMenu;

public plugin_init( ) {
    new hCallback = menu_makecallback( "MenuCallback" );
    
    g_hMenu = menu_create( "Some Menu", "MenuHandler" );
    
    menu_additem( g_hMenu, "You can press me", "1" );
    menu_additem( g_hMenu, "You can't press me", "2", _, hCallback );
    menu_additem( g_hMenu, "You can press me, too", "3" );
}

ShowMenu( client ) {
    menu_display( client, g_hMenu );
}

public MenuCallback( client, hMenu, iItem ) {
    // iItem starts at 0
    if( iItem == 1 ) {
        return ITEM_DISABLED;
    }
    
    return ITEM_ENABLED;
}

public MenuHandler( client, hMenu, iItem ) {
    if( iItem == MENU_EXIT ) {
        return;
    }
    
    switch( iItem ) {
        case 0: {
            client_print( client, print_chat, "You chose option #1" );
        }
        case 2: {
            client_print( client, print_chat, "You chose option #3" );
        }
    }
    
    ShowMenu( client );
}

register_clcmd( "say menu","ShowMenu");