One thing I often do in Dota is set up custom item builds, so that when I'm playing a hero all the items I like to buy as that hero are in the suggested items section of the shop, for quick, convenient access.
Often, when setting up these builds I like to start with the default build or a build on the steam workshop and tweak that a bit to suit my style. Unfortunately, when creating builds it looks like you have to start from scratch. Is that true, or is there some way that I'm not aware of to copy an existing build and then edit that?