A backbone's topology should be switchable from a toggle in the editor. Linear, Circular, and Chromosomal are not stored as a simple property today: Circular and Chromosomal are built from extra decorator glyphs on the backbone, and Linear is just their absence, so changing topology means adding or removing those glyphs by hand instead of picking a value. A backbone should expose a Linear/Circular/Chromosomal toggle that applies the choice and redraws the decorators.
A backbone's topology should be switchable from a toggle in the editor. Linear, Circular, and Chromosomal are not stored as a simple property today: Circular and Chromosomal are built from extra decorator glyphs on the backbone, and Linear is just their absence, so changing topology means adding or removing those glyphs by hand instead of picking a value. A backbone should expose a Linear/Circular/Chromosomal toggle that applies the choice and redraws the decorators.