Hay,
When you select Edit scketch (to modify it) from context menu(Edit profile Sccketch), when you finish modifying it, it satys visible, but it have to be hidden automaticly after you finish modifying scketch(like it does after you applying for example pull to skecth). Now after you modified existing sketch you have to hide it by hands, but would begreat if this action will perform automaticly.