Code:
on 1:INPUT:*: {
  if (/msg* iswm $1-) && (*serv iswm $2) && ($active != $+(@,$2)) { /echo -a Wrong Window! Type in the $+(@,$2) Window!) | halt }
  else if (/*serv* iswm $1-) && ($active != $+(@,$right($2, -1)) { /echo -a Wrong Window! Type in the $+(@,$right($2, -1) Window! | /halt }
}