I think this is because the Wall Closure is scripted in 2D only. This is what is displayed when the Symbolic option is selected.
However, when a "Projected" option is selected, ARCHICAD cuts the Wall and Windows 3D geometry with a horizontal plane and generates their 2D. In case of the Window, the Wall Closure geometry is not generated in 3D so it cannot be generated on the Floor Plan with the "Projected" option either.
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