I := 1;
    AddCount := 1;
    while I <= Length(Exts) do
    begin
      if Exts[I] = ';' then 
      begin
        P := I;
        if (WMPCount+AddCount) = WMPOpenMaxExt then break;
        AddCount := AddCount + 1;
      end;
      I := I + 1;
    end;
    if I <= Length(Exts) then Delete(Exts,P,Length(Exts) - P + 1);