Fix some inaccurate/misleading comments that led to said bug.
Gracefully handle the "impossible" case where we can't figure out a state ID
for an automation track, instead of crashing.
The idea here is to do the reasonable thing, and copy objects of some
type (e.g. MIDI region, gain line) to tracks with a matching type. The user
can override this with a track selection, which will be used straight-up.
Lost: ability to copy/paste lines across types, e.g. gain to pan. This is
often questionable, but sometimes useful, so we will need to implement some
sort of "greedy mode" to make it possible. Implementation simple, but not sure
what to do. Perhaps this should only be possible if one automation track is
explicitly (i.e. via track selection) involved, and the types are at least
compatible-ish?
This should probably hijack the same modifier as the guard points and work the
same on all automation tracks, but I did it this way to not change behaviour of
track automation where a default is much more reasonable.
No functional changes in this one (for easier auditing), but towards having
round up/down only if necessary modes, rather than kludging around that
situation with a double round as we do currently.
We shouldn't have to manually drive the drag here, but if the ARV handler
returns false, the event doesn't propagate correctly for some reason and the
drag is not driven by the Editor.
Two issues:
1) AutomationRegionView not receiving events (CC breakage).
2) Entered values must be rounded to integer for MIDI controllers. This should
be done more generically with ParameterDescriptor for all controls (also
supporting boolean toggles and such), once ParameterDescriptor becomes more
pervasive and takes over Evoral::Parameter, but this will do for now.
