Unfortunately we have to admit that the latest hotfix version of RadInput (2.1.3) introduces a bug when the Visible property for the input is set to false. The problem is already addressed and for your convenience we are attaching the custom trial build of RadCalendar here. The RadInput assembly is part of the zip and we provide the RadCalendar build for those who use RadDatePickers in their projects and want to migrate to this version of our input control.
If you need a developer version, please start a new support ticket and ask for it, we will send you the latest dev build via the support system. The hotfix will be officially available for Q3 2007 SP2 of RadControls. Note that the issue is not present in the Prometheus version of RadInput.
Please, accept our apologies for the temporary inconvenience.