procedure TForm1.PgCtrlMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var R: TRect;
begin
  R:= PgCtrl.TabRect(PgCtrl.ActivePageIndex);
  Label1.Caption:= Format('Mouse current point: %d : %d',[x,y]);
  Label2.Caption:= Format('Tab rectangle: Left = %d | Top = %d | Width = %d | Height = %d',
                          [R.Left, R.Top, R.Width, R.Height]);
 
  if (x > R.Left) and (x < (R.Left + ImgList.Width)) and (y > R.Top) and (y < (R.Top + ImgList.Height))
    then Self.Caption:= 'it''s inside of image'
    else Self.Caption:= 'it''s outside of image';
 
end;