[[escafandra]]

Empezado por Ziara

void __fastcall TForm1::ListViewCustomDrawItem(TCustomListView *Sender,
      TListItem *Item, TCustomDrawState State, bool &DefaultDraw)
{
 Sender->Canvas->Font->Color = clRed;

 if (snf2->Proto() == "TCP")
 {
  Sender->Canvas->Font->Color = clGreen;
 }
  if (snf2->Proto() == "UDP")
 {
  Sender->Canvas->Font->Color = clBlue;
 }
 if (snf2->Proto() == "ARP")
 {
  Sender->Canvas->Font->Color = clPurple;
 }
}

Prueba a añadir en tu código DefaultDraw = false;

void __fastcall TForm1::ListViewCustomDrawItem(TCustomListView *Sender,
      TListItem *Item, TCustomDrawState State, bool &DefaultDraw)
{
 Sender->Canvas->Font->Color = clRed;

 if (snf2->Proto() == "TCP")
 {
  Sender->Canvas->Font->Color = clGreen;
 }
  if (snf2->Proto() == "UDP")
 {
  Sender->Canvas->Font->Color = clBlue;
 }
 if (snf2->Proto() == "ARP")
 {
  Sender->Canvas->Font->Color = clPurple;
 }
 DefaultDraw = false;
}

Saludos.