[ecfisa]

Hola ingmichel.

En tu form MDIChild podrías hacer:

Código Delphi [-]
.....
implementation

uses Unit1; // frmMain

procedure TfrmChild.FormShow(Sender: TObject);
var
  i: Integer;
begin
  frmMain.ToolBar1.Visible:= False; 
  Toolbar1.Parent:= frmMain;  // Toolbar de frmChild
end;

...

procedure TfrmChild.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  ToolBar1.Parent:= Self;   // Toolbar de frmChild
  frmMain.ToolBar1.Visible:= True;
  Action:= caFree;
end;
end.

Saludos.