When we execute the PopupAtControl method to show the popup, we see a flickering in the left corner of our screen, showing the control that we use in the popup.
A solution for this is setting the visibility of the control to false in the DoPopup method, and set it back to visible after showing the form.
if Assigned(Control) and not (csDesigning in ComponentState) then
begin
Control.Align := alClient;
Control.Parent := frmC;
**Control.Visible := False; // <<<-------Set visibility to false**
{$IFDEF DELPHIXE10_LVL}
Control.ScaleForPPI(ScreenPPI);
{$ENDIF}
end;
....
frmC.Show;
frmC.Width := Round(ir.Width - 1);
frmC.Height := Round(ir.Height - 1);
frmC.Left := Round(ir.X + X);
frmC.Top := Round(ir.Y + Y);
SetWindowPos(frm.Handle, 0, X, Y, frm.Width, frm.Height, SWP_SHOWWINDOW or SWP_NOACTIVATE);
**Control.Visible := True; // <<<-------Add this line to make the control visible again after positioning of the form**