Note
Please note that this property is different from MdiChildren, which returns all MDI children of an MDI container form.
This property returns the forms that were shown by the ShowMdiChild method. If this form is an MDI container,
the result may contain fewer forms than MdiChildren. And if this form is an MDI child, the MdiChildren property is always empty,
whereas this property still may contain items. If this form is currently suspended, the SuspendingMdiChild property
returns the blocker form, which is an element of this property.