[CMake] VS2010 solution/project reload

[Andrea Galeazzi]

I'm currently dealing with a project requiring a lot of dependencies 
(74), so the structure of the CMakeLists.txt is as following:
project ( Main )
  add_subdirectory("W:/Lib1"  "${CMAKE_CURRENT_BINARY_DIR}/Lib1")
  add_subdirectory("W:/Lib2"  "${CMAKE_CURRENT_BINARY_DIR}/Lib2")
  add_subdirectory("W:/Lib3"  "${CMAKE_CURRENT_BINARY_DIR}/Lib3")
  ................
  add_executable( Main ${SOURCES} )
  target_link_libraries(Main ${LIB_TO_LINK})

When I choose  a VS2010 CMake generates a solution of 77 projects (74 
+Main + ALL_BUILD + ZERO_CHECK).
Now if I modify the CMakeLists.txt of one of the subproject and build 
the Main project VS2010 notify that many other project has been modified 
and also the solution. So, for instance, if I add a file to a subproject 
VS2010 shows a lot of dialog asking to reload the projects again and 
that's very frustrating!
My question is: is it a bug or a normal behavior? If the second, how can 
I avoid it?