The RadTimeBar does not use all of the intervals defined in its Intervals collection at all times to create periods (visualized as ticks or stripes in UI). Which interval(s) are used is determined by the amount of time that is currently displayed in the view. Periods are not created for intervals that do not fit in the currently visible time (VisiblePeriodEnd - VisiblePeriodStart).

For example, if the currently visible time period is 2h 30m (which is 150 minutes) in order for minute periods to be shown all of the 150 periods need to fit in the space available to the RadTimeBar. The control internally determines how many pixels each DateTime tick represents and based on that checks if an interval can be used in the currently displayed view.

Regards,
Vladimir Stoyanov
Progress Telerik