Ok, I didn't fully test it before so please ignore my previous posts.
I am still having problem. Here is what I did so far.
If I don't change
App_Code I get an error on "Select a control" section. Pls see image1. I can't do anything.
But if I change App_code to
App_SubCode_CSCode, I don't get an error under "Select a control". Pls see image2.
So, I can drag and drop the control to the page and change settings. I can save the page and publish it. It works fine.
But if I rebuild the website I get an error.
Can you please help?