// in FormCreate:
 
 with ComboBox1.Items do 
 
 begin 
 
   Add(IntToStr(clRed)); 
 
   Add(IntToStr(clFuchsia)); 
 
   Add(IntToStr(clBlue)); 
 
   Add(IntToStr(clGreen));
 
   Add(IntToStr(clYellow));
 
 end;
 
 procedure TForm1.ComboBox1DrawItem(Control: TWinControl;
 
   Index : Integer; Rect: TRect; State: TOwnerDrawState);
 
 begin
 
   with Control as TComboBox,Canvas do 
 
   begin 
 
     // fill the rectangle first with white
 
     Brush.Color := clWhite; 
 
     FillRect(Rect); 
 
     // then reduce it and fill it with the color
 
     InflateRect(Rect,-2,-2); 
 
     Brush.Color := StrToInt(Items[Index]); 
 
     FillRect(Rect);
 
  end;
 
 end;