approach used in several instances of previous work, such as [2, 8, 35], by hiding unchanged nodes to reduce clutter and drawing connectors to the reference to enhance juxtaposition; b) side-byside views [14, 26, 27] by going beyond pair-wise comparisons; c) existing work on subjunctive interfaces [30], TreeVersity [15– 17, 19] and TreeVersity2 [18, 19] to show a larger variety of difference visualizations.