ContextACObject is used by WPF-Controls and mostly it equals to the FrameworkElement.DataContext-Property. IACInteractiveObject-Childs in the logical WPF-tree resolves relative ACUrl's to this ContextACObject-Property.

VBContent is used by WPF-Controls. By setting a ACUrl in XAML, the Control resolves it by calling the IACObject.ACUrlBinding()-Method. The ACUrlBinding()-Method returns a Source and a Path which the Control use to create a WPF-Binding to bind the right value and set the WPF-DataContext. ACUrl's can be either absolute or relative to the DataContext of the parent WPFControl (or the ContextACObject of the parent IACInteractiveObject)