If the PeriodStart and VisiblePeriodStart is set to DateTime.MinValue zooming out using mouse wheel causes a crash. DateTime.Subract(TimeSpan value) method throws "ArgumentOutOfRangeException();". Looks like "TimeBarBase.CalculateLeftRightStep(this.SmallChange, centerOffsetPercentage, out leftStep, out rightStep);" does not calculate leftStep correctly.
RadTimeBar throws XamlParseException when current culture is arabic. Workaround: Create a custom class that inherits from Telerik.Windows.Controls.TimeBar.SelectionThumb and explicitly sets the TitleFormatString property to your custom format string in the constructor. Edit the Template of the RadTimeBar control - find the SelectionThumb instance in the template and replace it with an instance of the CustomSelectionThumb class.
When click and keep the mouse button down into the RadTimebar control and at the same time tap outside the application, InvalidOperationException is thrown. The issue is reproducible on Window 7 OS. Fix available in LIB Version 2016.1.328.
The value of the MinZoomRange property is incorrect after changing the the PeriodStart and PeriodEnd from code-behind. Fixed in Q3 2014