This is a known issue of the RadRotator control. I have raised its priority, nevertheless I cannot provide a firm estimation when a fix will be available. You can use the following bug report to follow the status of the issue, vote for it and comment it: http://feedback.telerik.com/Project/108/Feedback/Details/139180
For the time being you can try avoiding this behavior by setting a smaller value for the FrameDuration
property or disabling the PauseOnMouseOver
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