Version:           3.4.0 (using KDE KDE 3.5.6)
Installed from:    Unspecified Linux
OS:                Linux

Consider simple project from qt-x11-opensource-src-4.2.3/examples/qmake/tutorial:

$ ls
hello.cpp
hello.h
hellounix.cpp
hellowin.cpp
main.cpp

Then write _two_ project files:
1

tutorial.pro:
CONFIG += qt
include(add_options.pro)
SOURCES += main.cpp

2
add_options.pro:

HEADERS += hello.h
SOURCES += hello.cpp
TEMPLATE = app

with:
qmake-qt4 tutorial.pro
make
all works fine.

Now go to kdevelop:
kdevelop->Project->Import Existing Project...->
Project type: QT4 C++ Application (QMake4 based)

kdevelop scan project directory and select add_options.pro as main project file.
But add_options.pro isn't main project file.
Application can't be build.

gmake -k
g++ -c -pipe -pipe -Wall -W -D_REENTRANT  -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -I/usr/share/qt4/mkspecs/linux-g++-64 -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/ug++ -m64 -o add_options hello.o    -L/usr/lib64 -lQtGui -lQtCore -lpthread
/usr/lib64/gcc/x86_64-alt-linux/4.1.1/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: ld returned 1 exit status
gmake: *** [add_options] Error 1
gmake: Target `first' not remade because of errorssr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -o hello.o hello.cpp

Expected results:
Bring dialog window to select main project file from several *.pro files.