The changes tree registered drag sources only for rows that already belonged to a changelist, so files under Unversioned Files could not be dragged. Drag sources and drop targets are now separate: every file or folder row drags, and dropping unversioned paths on a changelist runs Add to VCS (git add) before moving them into that list.
Co-authored-by: panda-student <71381346+panda-student@users.noreply.github.com>