ShowMenu

This message displays a textmenu on the player's screen and waits for them to make a choice using the keys bound to slot1-slot0.  Their choice is sent as a menuselect client command, with the key pressed (0-9) sent in CMD_ARGV(1).

Short
 The valid choices for this menu.  This is a bitfield, so for a menu with choices 1,2 or 5, bits 1,2 and 5 should be set to one.
Char
 Display time in seconds.  If this is -1, the menu will be displayed until a choice is made or another menu is shown.
Byte
 NeedMore.  If true, then another ShowMenu message will be expected and will be appended to the end of this one.
String
 The menu text to display.  Limited to 192 characters(?)