Add a project that is using custom Makefiles. If you just add one folder (with a Makefile inside) to the build set and press the Build button respectively Project | Build Selection, all works fine. If you add another folder to the build set, the custom make file plugin first calls "make" in the second folder (which is a bug in itself because the build set should be built top down) with the output "*** Killed process ***" and the build aborts.
*** This bug has been marked as a duplicate of bug 372552 ***