I'm developing an VSIX extension under Visual Studio 2010 SP1. I used to debug it and experimental instance of VS was launching automatically. But after installing Visual Studio 2012 I started getting this error when trying to debug the same VSIX under the same VS2010:
A project with an Output Type of Class Library cannot be started directly.
In order to debug this project, add an executable project to this solution which references the library project. Set the executable project as the startup project.
How to fix this issue? How to make VS2010 launch experimental instance for debugging again?