I'm not sure why, but Visual Studio is not showing all the projects in my solution. I need them to show so I can set as default project under solution explorer. I'm not seeing a fix for this issue in a general internet search. The closest I see is VS not showing files folders, but this is different than my issue. Hopefully there is an easy way to fix it, without adding things again piecemeal. My co-workers can see their complete set of projects in solution explorer so it must be a corruption in my workspace.
Open your ".sln" project file using Notepad. In this file you can observe listed projects like below
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "test.myProject.Data", "test.myProject.Data\test.myProject.csproj", "{6D7F7B84-F3BD-4A19-A069-D144C345B887}"
EndProject
Please add if there any missing projects. If you have old back up or co-workers file, Just copy and paste missing projects to this file. In my case it works !!