Qt Creator include paths on Windows

Hi, I am trying to build a simple project in Qt Creator under Windows using the 5.1 opengl/msvc 2012 64-bit release, but it seems that INCLUDEPATH/DEPENDPATH are not working properly. For example, if I edit the project’s .pro file and add INCLUDEPATH += foo DEPENDPATH += foo and then build the project, there is no “foo” in the compiler output, and then any source files including any files in that ‘foo’ directory or any of its sub-directories fail to compile. Could anyone provide any light on this? Thanks.