catkin_make and catkin_tools not finding new msg/srv?

edit

When I add a new .msg (I confirmed for .srv as well) and running catkin build, the new file doesn't seem to be processed. Is this expected, or is there a way to let it find new definition? This doesn't seem to be is also a case with catkin_make.

CWS_PROOV=/tmp/cws_proof
mkdir -p "$CWS_PROOV"/src
cd "$CWS_PROOV"/src
git clone git@github.com:130s/prooving_grounds.git        <-- Merely beginner_tutorials with minor change
cd "$CWS_PROOV"
catkin b
ll ./devel/lib/python2.7/dist-packages/beginner_tutorials/msg
source devel/setup.bash 
roscd beginner_tutorials/
echo "int64 num" > msg/Num4.msg
cd -
catkin b
ll ./devel/lib/python2.7/dist-packages/beginner_tutorials/msg
total 24K
drwxrwxr-x 2 rosnoodle rosnoodle 4.0K Mar 17 14:23 ./
drwxrwxr-x 3 rosnoodle rosnoodle 4.0K Mar 17 14:23 ../
lrwxrwxrwx 1 rosnoodle rosnoodle  111 Mar 17 14:23 __init__.py -> /tmp/cws_proof/devel/.private/beginner_tutorials/lib/python2.7/dist-packages/beginner_tutorials/msg/__init__.py
lrwxrwxrwx 1 rosnoodle rosnoodle  108 Mar 17 14:23 _Num2.py -> /tmp/cws_proof/devel/.private/beginner_tutorials/lib/python2.7/dist-packages/beginner_tutorials/msg/_Num2.py
lrwxrwxrwx 1 rosnoodle rosnoodle  108 Mar 17 14:23 _Num3.py -> /tmp/cws_proof/devel/.private/beginner_tutorials/lib/python2.7/dist-packages/beginner_tutorials/msg/_Num3.py
lrwxrwxrwx 1 rosnoodle rosnoodle  107 Mar 17 14:23 _Num.py -> /tmp/cws_proof/devel/.private/beginner_tutorials/lib/python2.7/dist-packages/beginner_tutorials/msg/_Num.py
ll /tmp/cws_proof/devel/.private/beginner_tutorials/lib/python2.7/dist-packages/beginner_tutorials/msg
    (Num4 not found)
ll ./devel/share/gennodejs/ros/beginner_tutorials/msg
    (Num4 not found)
ll ./devel/share/common-lisp/ros/beginner_tutorials/msg
    (Num4 not found)

$ apt-cache policy python-catkin-tools|grep Inst
  Installed: 0.4.4-1

To work this around I'm removing build, devel before building. After modifying CMakeLists.txt also works for me. Seen on Xenial Kinetic and Trusty Indigo.

UPDATE After listing all .msgs and .srvs in CMakeLists.txt both catkin_make and catkin build seem to find the new files and update to the existing files. It'd be still nice if there's a way to achieve the same without listing them.