The RadChart control automatically handles change notifications coming from its items source as soon as the items source itself is an ObservableCollection. However, most often the visual content is fully redrawn when data changes. This behavior is going to change in some of the upcoming releases but a specific time frame can not be committed.
Doing on screen data manipulation is also a subject of future development and it is present in our to-do list for a future version of the control.
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