Returns the amount of text the menu can still hold. If this is limit is reached or overflowed, the text is silently truncated.
Radio menus: Currently 511 characters (512 bytes). Valve menus: Currently -1 (no meaning).
int GetPanelTextRemaining(Handle panel)
A MenuPanel Handle.
Number of characters that the menu can still hold, or -1 if there is no known limit.