Thanks Heath for your reply. I have gone through the CAS article you had suggested. It is very informative. However, I have to still go through it a couple of times before I can digest. The impression I got is that CAS is for stopping unauthorized user to execute the code. However, the problem I have been facing is at design time. For the problem to be easily understood, I have created a small project. I am attaching a zip file of the project. This project successfully compiles. You can execute the same. But to observe the current problem, do the following: Open the solution in VS 2003. This contains a Test project. This contains three forms - FrmMain, CSIBaseForm, FrmUser. FrmUser inhertis from CSIBaseForm which in turn inherits from System.Windows.Forms.Form. I double click on the FrmUser form to view it in design mode. It does not show. Could you tell me what the problem is and what I should do to overcome it? There does not seem to be a way of attaching the zip file here. I shall send it directly to your e-mail address. Thanks.
