I am drawing administrative regions that have boundaries follow streets in another layer. As these streets are pretty long with many vertices, I don't want to re-trace them. I am looking for a way to "split" the polygon like "split features" tool (the one with the scissors icon).
Before: one whole polygon with a line running through it
After: the line works as a pair of scissors and split the polygon into 2 parts (in the picture below, the polygons were moved apart for illustrating purpose only)