Thanks for your report.
We are aware of this issue. It is due to the fact that the diasbled and enalbled states of the DatePicker's inout box do not differ. Hence, the problem appears. When you enable the datepicker its appearance does not change. It is simply the fact that you mouse over the input box and input's border gets highlighted.
We will surely be looking into solving the problem with the forthcoming Q1 due in March.
Your Telerik points have been updated for your involvement.
the Telerik team
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