I'd like to agree with this question. I cannot get MDI to work, either.

I suppose the answer to MDI under Linux is tabs, but I was hoping I'd be able to use an MDI interface instead. *sigh* When I create a new MDI child, it seems to create a whole new window outside the parent container.
procedure TmainForm.mainFormShow(Sender: TObject);
var
child : Tmud_win;
begin
child := Tmud_win.Create(Application);
child.show();
end;
I even tried to Create(mainForm), that didn't help, either
