I have a web user control within ASP.NET web application, and When I am trying to edit Front-code, I got unexpected behavior! where the ASP.NET controls have been disappeared and the design view became a blank as shown below !
It’s occasionally occurred if there’s an error in front code !
In my case, I make sure that there are no errors in front code that has been reviewed carefully.
Note : If the User Control reference a a CSS style-sheet you should also check it and ensure that it’s cleaned from error.
After a long investigation trip , I decided to move any CSS code to the bottom of user control.
After moving CSS codes and CSS files to the bottom of user control. I surprised where I can now edit Front-code without missing the design view.