I’ve built a brand new application in RBS to test the environment. I did not touch any letter of code after creating the application and tried to edit index.razor in designer. No luck.
I am sending you a screenshot of my attempt and complete code of newly created application with the hope that you can explain to me where I went wrong.
The attached application builds and edits just fine with the latest version of Radzen Blazor Studio 1.56.2. Here is my experience with it.
Your screenshot shows there is some build error. Can you tell us what the error is? You can check the output window. You can also run the analysis from the Help / Analyze Application menu item.
There was an error. That error was caused by nuget packages that were installed and for some reason RBS was trying to access this library. I removed this library from my laptop and now RBS works.