classesToDraw := Collection withAllSubclasses.
view := ROMondrianViewBuilder new.
view interaction popupText: [:entity | entity name ].
view shape rectangle 
borderWidth: 1; 
borderColor: Color blue.
view nodes: classesToDraw.
view gridLayout.
view open

Result: Error (Red rectangle)
=========================================
classesToDraw := Collection withAllSubclasses.
view := ROMondrianViewBuilder new.
view interaction popupText: [:entity | entity name ].
view shape rectangle 
"borderWidth: 1; "
borderColor: Color blue.
view nodes: classesToDraw.
view gridLayout.
view open

works fine.

Can you please check?