Hi Heinz @strudel ,
As far as I know, Increment Snapping always Snaps with the Objects Origin (and in Edit Mode with the average of the Selected Vertices, so Adrian’s method won’t work…I must admit that that was my first guess as well, though).
The best way, I can think of, is to place the Cube with the corner you want to Snap to the Grid on a Grid Point and then enable Snapping with Absolute Grid Snapping disabled.
