function TControl.ClientToScreen(const Point: TPoint): TPoint;
var
  Origin: TPoint;
begin
  Origin := ClientOrigin;
  Result.X := Point.X + Origin.X;
  Result.Y := Point.Y + Origin.Y;
end;

function TWinControl.GetClientOrigin: TPoint;
begin
  Result.X := 0;
  Result.Y := 0;
  Winapi.Windows.ClientToScreen(Handle, Result);
end;