This is a duplicate of http://feedback.telerik.com/Project/108/Feedback/Details/210060, see there for a workaround and for status updates. You can change the DPI settings in Windows from the Display Settings. Setting a size of 125% and clicking on a button will throw a server exception: ------- Input string was not in a correct format. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.FormatException: Input string was not in a correct format. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [FormatException: Input string was not in a correct format.] System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +12526913 System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +120 Telerik.Web.UI.RadImageButton.LoadPostData(String postDataKey, NameValueCollection postCollection) +256 Telerik.Web.UI.RadWebControl.System.Web.UI.IPostBackDataHandler.LoadPostData(String postDataKey, NameValueCollection postCollection) +16 System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad) +457 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1833