3D perspective & transparency playing tricks ?

Hi Rooters,
the attached macro shows the two boxes representing an example of displying the ideal and the post-alignment nodes (it's a small example I did for myself to understand the Align() method and to get hold on "which axis is which in the local frame" ;)).

When viewing the result using GL viewer One may notice (correctly). that the green box is positioned closer to the XY plane (with the set of alignment parameters like inside the attached macro). But, rotating the view about the Y axis
the volumes start to move respective to each other, which may be an illusion, but illusions do not make objects positioned more far from XY plane closer than the other when the viewport is rotated by some 90 degrees :).

Regards
Michal