var
APoint: TPoint;
APoint2: TPoint;

procedure TForm1.FormCreate(Sender: TObject);
begin
  APoint := Point(-1,-1);
  APoint2 := Point(-1,-1);
end;

procedure TForm1.ImageEnView1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if APoint.X < 0 then
  begin
    APoint := Point(X,Y);
    exit;
  end;
  if APoint.X > 0 then
     APoint2 := Point(X,Y);
  if (SelectOnClick1.Down) and (APoint.X > 0) and (APoint2.X > 0) then
    ImageEnView1.Select(APoint.X, APoint.Y, APoint2.X, APoint2.Y);
end;

 { Private declarations }
 AClickCount: Integer;
 AStartX: Integer;
 AStartY: Integer;
 AEndX: Integer;
 AEndY: Integer;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ImageEnView1.MouseInteract := [miSelect];
  AClickCount := 0;
end;

procedure TForm1.ImageEnView1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
{ This allows making a selection with two mouse clicks.  Clicking outside of the selection clears the selection }
 { A selection may be moved or resized. }
begin
  if ClickSelect1.Checked then
  begin
    Inc(AClickCount);
    {If selected and clicked outside of selection then deselect}
    if (ImageEnView1.Selected) and
      (not ImageEnView1.IsPointInsideSelection(X, Y)) and (AClickCount >= 3)
    then
    begin
      ImageEnView1.DeSelect;
      AClickCount := 0;
      AStartX := -1;
      AStartY := -1;
      AEndX := -1;
      AEndY := -1;
      exit;
    end;
    if not ImageEnView1.IsPointInsideSelection(X, Y) then
    begin
      if AClickCount = 1 then
      begin
       { set point 1 }
        AStartX := X;
        AStartY := Y;
        Exit;
      end;
      if AClickCount = 2 then
      begin
        { set point 2 }
        AEndX := X;
        AEndY := Y;
        ImageEnView1.Select(AStartX, AStartY, AEndX, AEndY);
      end;
    end;
  end;
  {Note: ImageEnView1.MouseInteract must be [miSelect], otherwise cursor handling must be handled in order to have the correct cursors appear when the mouse is inside the selection or over the resizing grips.
   In addition code to drag or resize the selection must be added if MouseInteract is not [miSelect] }
end;