Changing source does not trigger compilation

Here is how I built my package:

> python setup.py bdist_wheel --build-type RelWithDebInfo -j 4 -- -DVTK_Group_Web=ON -DVTK_SOURCE_DIR="c:/Work/VTK/VTK"

Then if I change files within c:/Work/VTK/VTK, the package is not re-built, simply installed.