The INCLUDE directory tree contains include files for most parts of XWorkplace. Modify setup.h to adjust global compilation #define's. That file is #include'd with all source files from the subdirectories of "src\". The main INCLUDE directory is included in the INCLUDE path by the makefile. As a result, you have to specify the subdir with #include, e.g. #include "startshut\apm.h". See PROGREF.INF for details.