Thank you for writing.
In Q2 2013 a new version of RadTrackBar was released, which explains the exceptions you are getting. You can see the changelog here
. For the latest version of RadTrackBar you can set transparent background to the thumb as follows:
TrackBarThumbElement thumb = (trackBar.TrackBarElement.BodyElement.IndicatorContainerElement.Children
thumb.GradientStyle = GradientStyles.Solid;
thumb.BackColor = Color.Transparent;
Hiding the ticks can happen by setting of the TickStyle
trackBar.TickStyle = TickStyles.None;
You can also read the documentation of RadTrackBar here
I hope this helps.
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