The Arranger section, when copying / moving, "catches" only the events strictly within the time range of the given arranger section. In the real music world, this functionality is not always enough. In many cases, the first sounds of instruments have to start just before the formal beginning of the bar (or section of the arrangement).
As a further enhancement of the arranger's functionality, I would see the possibility of individual extension of particular arranger sections, individually for each path.
Initially (as so far), with some section of the arranger should be associated a given range of part, compatible in time. But if necessary, one could broaden (or shorten) the ranges of the given arranger section (independent for each path) by events or sounds from its immediate neighborhood. The point is that the scope of such an extension can be independent, for parties from different paths. After such an operation, copying / moving would not cause clipping of events (or sounds), which are intentional to be assigned to a given section of the arranger. Usually it is about 1/4 measure, one note or about 1 second of sound, or some other, depending on the music style.
I think that the usefulness of this solution is important with further aspects:
In my program version (3.5.4 on PC), almost all audio tracks that have been recorded from external instruments through MIDI are presented on grid slightly shifted in time "forward". The result is that if a midi note occurs exactly at the beginning of the given arranger section, the recorded audio sound is minimally cut when moving the arranger sections.
A similar situation will occur if a section ends and the sounds have not yet resounded.