I think it means that if this parameter is referred to in a Graphic Template, it will actually display the drawing of the Zone Polygon currently being listed.
Laszlo
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I think it is mentioned in the GDL Manual. Or check the following link on ArchiGuide: http://www.graphisoft.com/support/archicad/archiguide/simpleelementsched.html
It talks about Elements, not Zones, but it has an example of how to create a drawing for the element which will be displayed in the list.
Laszlo
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD 2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28