For one of the solutions, I don't see the Clean Solution option neither in the context menu when I right click on the solution name in the Solution Explorer nor in the Build menu. When I make any changes to the project and debug, VS never hits the break point and I get the "The breakpoint will not currently be hit. The source code is different from the original version." message. My understanding is that I need to clean the solution.
For other solutions, I do see the Clean solution and I don't have the same issue.