Found the real problem :-)
In the resizewindow part i already 'publish' the projectionlocation matrix, but the location is not known yet and default being 0. But when requested its location becomes 1 resulting that it is overwritten by the modelview matrix that gets location 0. So as a workaround i calculate the matrix as before but only 'publish' it in the init part.
And next the cube showed up :-)

Final source: http://www.noeska.net/downloads/Ogl3Cube4.zip