Are you sure qt_module_title is passed to slicerMacroBuildQtModule in your cmakelists ?
and that qSlicerGetTitleMacro(QTMODULE_TITLE); is defined in your qSlicerDoseVolumeHistogramModule header ?

I agree that the title should be set the same way all across the modules (not the case).

I added the row
TITLE ${qt_module_title}
in the slicerMacroBuildQtModule macro in the module's CMakeLists.txt and the module name appears correctly, thanks!

However, the qSlicerGetTitleMacro(QTMODULE_TITLE) fails to compile in the header, because the module name is not in quotation marks.
The funny thing is that I have two very similar modules, and this problem occurs only with the one whose skeleton I generated yesterday with the python module template generator. The older one works fine, the macro's value (the module title with spaces) is between quotation marks.

Looking at the build log, the title is quoted. Indeed the parameter is passed as: -DQTMODULE_TITLE="\"Bar Foo\""

I am assuming this occurs on Windows ?

[20%] Building CXX object CMakeFiles/qSlicerLoadableExtensionTemplateModule.dir/moc_qSlicerLoadableExtensionTemplateModule.cxx.o
/usr/local/bin/c++ -DqSlicerLoadableExtensionTemplateModule_EXPORTS -DQT_SCRIPT_LIB -DQT_SVG_LIB -DQT_UITOOLS_LIB -DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_TEST_LIB -DQT_XML_LIB -DQT_SQL_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQTMODULE_TITLE="\"Bar Foo\""

Yes, it is Windows.
What I have in the build log is ... /D "QTMODULE_TITLE=Dose Accumulation" ...

It seems the problem is not related to the fact of having space in a preprocessing symbol. After doing a small test on windows (VS2008 / 64bit / CMake 2.8.8), it doesn't seem to cause trouble. See enclosed sceenshot.

Yes, this problem does not occur in every case. As I said, one of two modules (both of which I created practically the same way) works like yours, and the other has the issue of the missing quotation marks. As the relevant parts in the CMakeList files are the same, I have no idea what can be the difference that causes this.
I also use VS2008 / 64bit / CMake 2.8.8.
The two modules in question are
https://subversion.assembla.com/svn/slicerrt/trunk/SlicerRt/src/DoseVolumeHistogram <- works fine in this sense
https://subversion.assembla.com/svn/slicerrt/trunk/SlicerRt/src/DoseAccumulation <- quotation mark issue
I'll try with a clean build, but in the meantime I would really appreciate if you could take a quick glance at these modules (the CMakeLists.txt and the ...Module.h files).
Thanks!

Let me know if a clean build prevent the issue from occuring.

I reviewed both main CMakeLists, I created an issue and added my comment to it. See 0002026

The clean build solved the issue.
Thank you very much both for your help!

Excellent - if everything is working as expected, please consider closing this issue.

Yes, everything works fine, thanks again!