[델파이] Cannot hide and MDI Child Form

unit Unit2; 

interface 

uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs; 

type 
  TForm2 = class(TForm) 
    procedure FormClose(Sender: TObject; var Action: TCloseAction); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
    procedure VisibleChanging; override; // <<-- 요기
  end; 

var 
  Form2: TForm2; 

implementation 

{$R *.dfm} 

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction); 
begin 
  Action:=caHide; 
end; 

procedure TForm2.VisibleChanging;  //  <<-- 요기 
begin 
 // inherited; 
end; 

end.

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