[CMake] Changes to CMAKE_CXX_FLAGS_RELEASE not reflected in GUI

[digitalriptide]

Dear CMake Community,

I would like to add an extra flag to CMAKE_CXX_FLAGS_RELEASE (-xHost
for Intel compilers), so in my CMakeLists.txt I add:
set( CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -xHost" )

If I then run VERBOSE=1 make, I observe that the xHost flag is passed
to the compiler. If I view the GUI, however, (ccmake ..), and switch
the view to advanced, the flags are still listed as the default (-O3
-DNDEBUG).

Is this the intended behavior? Is there a way to specify additional
release build flags in CMakeLists.txt and have them reflected in the
GUI?

Thank you for your recommendations!