Currently, TimeBar does not provide possibility for changing the quarter numbering according to a fiscal calendar. We consider including the ability for creating custom intervals, however we are still collecting ideas on how customers would like to customize the control. I forwarded your scenario to our developers. Also, for the upcoming release we are going to introduce IntervalSpan property which will provide functionality for grouping the interval items together. For example you will be able to group the MonthInterval by 3, starting from the TimeBar.PeriodStart date.
I hope that this information helps.
the Telerik team
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