Disable or remove MDI child form minimize and restore actions

Question

I want to remove or disable the buttons inside the main menu, that controls the child form (minimize, restore), of my application.

The application should look like a "browser", where the MDI child forms must stay maximized all the time.

I alreday tried to disable they, by setting

BoderIcons := [biSystemMenu];

But I got this:

I alreday tried to disable the menu commands at the WM_INITMENU message, but without success:

procedure WMInitMenu(var Message: TWMInitMenu); message WM_INITMENU;

procedure TMyMDIChildForm.WMInitMenu(var Message: TWMInitMenu);
begin
  inherited;
  EnableMenuItem(Message.Menu, SC_MAXIMIZE, MF_BYCOMMAND or MF_GRAYED);
  EnableMenuItem(Message.Menu, SC_MINIMIZE, MF_BYCOMMAND or MF_GRAYED);
end;

I'm using:

• Delphi 7.1 Enterprise
• Windows 7 Pro x64

Answer 1

I solved by intercepting the WM_COMMAND at the MainForm as the follow code shows:

type
  TMDIMainForm = class(TForm)
  protected
    procedure WMCommand(var Message: TWMCommand); message WM_COMMAND;
  end;

implementation

procedure TMDIMainForm.WMCommand(var Message: TWMCommand);
begin
  case Message.ItemID of
    SC_CLOSE, SC_MINIMIZE, SC_RESTORE, SC_MAXIMIZE:
      begin
        Message.Result := 0;
        Exit;
      end;
  else
    inherited;
  end;
end;

At the child forms, I simple placed this:

procedure TMDIChild.OnCreate(Sender: TObject);
begin
  WindowState := wsMaximized;
end;

Now my MDI childs stays maximized and the user isn't able to restore or minimize than.