//from1 is MDIform,form2 is mdichild
procedure TForm1.maxClick(Sender: TObject);
begin
if form2=nil then
form2:=tform2.Create(application);
form2.WindowState:=wsMaximized;
form2.Show;
end;
procedure TForm1.smallClick(Sender: TObject);
begin
if form2=nil then
form2:=tform2.Create(application);
form2.WindowState:=wsMinimized;
form2.Show;
end;
procedure TForm1.normalClick(Sender: TObject);
begin
if form2=nil then
form2:=tform2.Create(application);
form2.WindowState:=wsnormal;
form2.Show;
end;