# also assuming that you also have static headers in the include folder of your package
include_directories(include ${CATKIN_DEVEL_PREFIX}/include)  You should always only add the include folder (rather then the package specific subfolder in it) and then include your code with the package name as a namespace (e.g. #include <pkgname/myheader.h). Second to make packages work which depend on yours you have to export both include locations: catkin_package(INCLUDE_DIRS include${CATKIN_DEVEL_PREFIX}/include)

For the install case it will work correctly since the include folder in install space will contain your static headers form the package include folder (if you have also installed them) as well as the header installed from the devel space. Again keep in mind that all your headers should be in a subfolder of include and should also be referenced like this in code.