Currently (build 13037) if you highlight a selection (block, line or string) and press ctrl-d it copies the selection and keeps the highlighted selection on the newly inserted block. But if you drag or ctrl-drag the selection rather than pressing ctrl-d it doesn't keep the highlighted selection on the newly inserted block. Keeping the highlighted selection for the drag operations in the same way as ctrl-d does would be useful for things like multiple copies or moving a selection somewhere else. I've always found it a useful feature in editors that support it.