If I place a leader, then edit it by double clicking, the leader will lose history. I can successfully edit in the properties window without history breaking.
Also, it would be nice if leaders mirrored a bit more elegant. The big issue is with a mirrored leader, text width control point no longer functions. You can select it and move it around, but it does not affect the text wrapping. The other thing that would be nice is if the justification was modified upon mirroring. By this I mean that if leader text is left justified before mirroring, and I mirrored the leader left / right, it would be nice if the mirrored text was right justified. Same for vertical justification when mirroring up / down.