We are already aware of the observed by you issue. It is caused by the higher (bigger than 100%) DPI that is currently applied on your machine. The issue is logged in our feedback portal and you could vote for the item and track its status on the following link:
Currently, the only workaround that we could suggest you is to change the DPI to 100%.
However, I am glad to inform the priority of the issue has been raised and currently our development team is working on it. So, please follow the item and as soon as the issue is fixed you will be notified.
Meanwhile, if you have any additional questions or concerns regarding Telerik controls, please do not hesitate to contact us.
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