Hi,
This is the issue with DateTimeEdit control in the version 8.3.0.22. We have fixed this DateTimeEdit repeat button issue in our latest version.
Please try to upgrade to our latest version of Essential Studio and try to use our DateTimeEdit control.
You can download the latest version from the following location,
http://www.syncfusion.com/support/forums/general/98103/Essential-Studio-2011-Volume-1-Final-Release-v91020-available-for-downloadPlease let us know if you face any issues in the new version. We will be able to help you out.
Regards,
Boopesh