InstallConanDepsIfRequired() iterates over DTE.Solution.Projects, which doesn't contain projects within solution folders. Instead, DTE.Solution.Projects contains an item for the solution folder of type vsProjectKindSolutionFolder and that would need to be iterated over separately to find contained projects.
Consequently, if you have projects within a solution folder, the conan files you may add to those projects are not found upon opening the solution or changing the active solution configuration.
InstallConanDepsIfRequired() iterates over DTE.Solution.Projects, which doesn't contain projects within solution folders. Instead, DTE.Solution.Projects contains an item for the solution folder of type vsProjectKindSolutionFolder and that would need to be iterated over separately to find contained projects.
Consequently, if you have projects within a solution folder, the conan files you may add to those projects are not found upon opening the solution or changing the active solution configuration.