Now a recording have only one length value (usually the one of the firstly added track), though some recordings include dozens of merged tracks having very different durations. The sole length value displayed for a recording with many included tracks is spurious and even deceitful.
It would be very useful to display two length values for a recording: the minimal and the maximal ones, which should be changed automatically after each merging. (When a recording includes a sole track, these two values will be naturally same.)