If a form owns another form, the owned form will be always displayed in front of its owner form, no matter which is the active form. This makes owned forms ideal for implementing tool and palette windows. Another feature of owned forms: when the user closes or minimizes the owner form, all the owned forms are also closed or minimized. When minimized, the owner forms and all its owned forms count as one icon in the Windows taskbar.
In Visual Basic 6, you can display a form as an owned form by passing Me as the second argument of the Show method, as in:
You can't pass any argument to the Show method under Visual Basic .NET, but you declare that the callee form is owned by the caller form by invoking the AddOwnedForm method:
' The Visual Basic 6 way for creating an owned form
Dim frm As New CalleeForm
frm.Show , Me
A form can detect whether it is being owned by another form using the Owner property; a form can enumerate its owned forms by iterating over the collection returned by the OwnedForms property.
' The Visual Basic .NET way for creating an owned form
Dim frm As New CalleeForm()
' Add this form to the list of owned form.