[iGetty]

It's easy.

Make a player variable;

pawn Код:

new DialogShown[MAX_PLAYERS] = 0;

public OnPlayerConnect(playerid)
{
    DialogShown[playerid] = 0;

    if(DialogShown[playerid] == 0)
    {
        //your code
        DialogShown[playerid] = 1;
    }
    //Rest of your code
}

There mate.