If User specifies that some header/source files should be loaded only for windows and some for Mac, and specifies same in .pro file. The project view should not show/include the files not meant for the current OS. Say, following is the .pro file

SOURCES += \
        main.cpp
macx{
 HEADERS+=mac.h
 SOURCES+=mac.cpp
}
win32{
 HEADERS+=windows.h
 SOURCES+=windows.cpp
}

It is expected that windows.cpp and windows.h should not be shown in the project view when the project is loaded on Mac and vice-versa.