Why does the horizontal/vertical display of the process graphics (block layout) appear inconsistent?

The horizontal/vertical display of the process graphics (block layout) seems to have been mixed up.

If you select a Main Process that currently only exists of Main or Sub Processes, the graphical representation horizontal/vertical seems to be reverse. For example, shapes in the horizontal view are displayed below each other (and not next to each other as ecpected). 

However, as you can see, the subordinate processes do not contain any connections between each other, i.e. they are all treated as potential start objects and therefore all are shown in the horizontal view on the left. If another object is modelled in the graphic, it can be seen that this object is then placed to the right of it and connected with an arrow.

The same behaviour can be transferred analogously to the vertical view and to the swimlane view.