MDI Child Forms at Design Time

At design time, child forms are not restricted to the area inside the MDI form. You can add controls, set properties, write code, and design the features of child forms just as you would with any other Visual Basic form.
You can determine whether a form is an MDI child by looking at its MDIChild property, or by examining the Project Explorer. If the form's MDIChild property is set to True, it is a child form. Visual Basic displays special icons in the Project Explorer for the MDI and MDI child forms, as shown in Figure 6.5.

Figure 6.5   Icons in the Project Explorer identify MDI child, standard, and MDI forms