There is a little trick in it, so many beginners get confused when reading a usual MSDN help page:
http://msdn.microsoft.com/en-us/library/system.windows.forms.form.aspx[
^].
The reason is: there is no such concept as "open a form", even though a form can be closed. You simply create a form with its constructor and later call the method
Show
or
ShowDialog
to show imitating modal dialog behavior. However, I strongly recommend to use the relationship owned form / owner form, so better keep the main form and owner of all other non-modal forms, use
AddOwnedForm
, please see:
http://msdn.microsoft.com/en-us/library/system.windows.forms.form.addownedform.aspx[
^].
That's it.
And yes, better never use MDI, don't torture yourself and scare off your users with this ugly design style. If you have questions on it, I'll explain.
—SA