FWIW, I've noticed a similar problem when I open and manipulate a .pcb file generated by pstoedit. When I try to move the polygons generated by the 'pcbfill' pstoedit output driver onto the 'silk' layer, they vanish instead of moving. I have to edit the .pcb file in a text editor to move the polygons to the silk layer.
FWIW, I've noticed a similar problem when I open and manipulate a .pcb file generated by pstoedit. When I try to move the polygons generated by the 'pcbfill' pstoedit output driver onto the 'silk' layer, they vanish instead of moving. I have to edit the .pcb file in a text editor to move the polygons to the silk layer.