when I bind the TaskSource of the RadGanttView (WPF) to a CompositeCollection I get the Exception "Object of Type System.Windows.Data.CollectionContainer cannot be converted to Type IGanttTask". With the RadTreeView it works. All Items in the Collections implements IGanttTask.
In its current implementation RadGanttView does not support binding the TasksSource to CompositeCollection. You could log this as a feature request in our Feedback Portal. We will review the item and we will consider it for implementation.
Hope this information will be helpful for you.
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