如前所述，您的设计是错误的，那么您可以删除触发器并手动操作：

// show or hide shadow effect
procedure TForm2.ShowShadowEffect(AValue: boolean);
begin
  if ShadowEffect1.Enabled <> AValue then
    ShadowEffect1.Enabled := AValue;
end;

// show when enter on panel
procedure TForm2.Panel1MouseEnter(Sender: TObject);
begin
  ShowShadowEffect(True);
end;

// hide when leave the panel
procedure TForm2.Panel1MouseLeave(Sender: TObject);
begin
  ShowShadowEffect(False);
end;

// keep visible when over button
procedure TForm2.Button1MouseEnter(Sender: TObject);
begin
  ShowShadowEffect(True);
end;