(RizomUV 2018.0.70) In Edge mode, when making selections with the SHIFT key, it often happens that selection is branching into two directions then follows only one, leaving a wrong branch that we need to delete afterwards (see attached). The algorithm should be smart enough to avoid these branches so we end up with a single line.
Also, using SHIFT selection sometimes ends with a white edge I am not sure how to get rid of besides left clicking in the view which removed all selections, then using Undo to restore the last selection, this time without the white edge. Again, this is awkward. The SHIFT selection is a very good idea, but I think its current implementation needs to be improved.
The white edge is there to to preview the shortest path. But it is true that the preview remains if the SHIFT key is released when the mouse pointer is over an edge. This allows to orbit/pan/zoom without loosing the path preview, which can be seen as a good thing sometimes.