The MSDN Library, that came with the May community preview, wouldn't show any of the topics. The solution was to change the binding "dexplore.exe" from the v2.0.40507 to v2.0.40426 in the "dexplore.exe.config"-file in the install directory, since that version of the framework is installed.

[update: I just noticed this is descriped in the readme, in point 18.2.]