Short explanation: Select a trace segment then keep tapping the ‘e’ key to expand the selection to the whole trace.
Longer explanation: In Upverter, traces are broken up into segments. When you click on a trace the related segment gets selected. This single-segment selection is helpful in situations where you’ve routed most of a trace but need to re-route or adjust the last little bit. However, you sometimes want to select the whole trace (ie. if you want to delete it). Select one of the segments then keep hitting the ‘e’ key to expand the selection by an additional segment on either side.
Another way to select multiple segments is to hold Shift while clicking on the desired segments.