This involved a significant change in event handling for automation region views,
but it brings it into line with how it works for other things. On button press
we initiate a drag, then if no motion occurs, the Drag returns false during
finalization, and only then do we continue through Editor::button_release_handler()
to eventually end up in ::add_automation_event().
Although it is a substantial change, the fact that it now works the same
way for audio regions, automation regions and automation tracks seems
like a definite plus.
Drag::_raw_grab_time is set to the correct time-domain. However
during ::motion() and other operations the adjusted time was
always AudioTime.
Most notably this caused editor->selection->time to have
different time-domains for start and end.
This prevents overlap of successive hits.
Ardour 7 added a new duration select drop-down menu,
which defaults to "Auto" (musical grid) and removed
the special case when drawing percussive notes.
It was possible to accidentally create overlapping notes,
without the user being aware of doing so.
Make click & drag in the left-hand half of a region with the Timestretch
tool stretch the region on its left, leaving the end position of the new
time-stretched region in the same place as the end of the original.
Editor::motion_handler() only updates the snap-cursor
when no drags are active. While dragging, Drag::motion is
responsible to set the cursor accordingly.
In many cases the snap-cursor simply remained stuck at
the most recent position. Since in many cases
(e.g. RubberbandSelectDrag) it makes no sense to show the
cursor, so Drag::start_grab now hides the cursor by default.
This also fixes cases where the cursor is shown, but
was displayed in the wrong location.
* the process of tempo mapping requires/encourages you to click on the
last-known good marker, before continuing to make tempo tweaks
* this conflicts with the idea that clicking in a ruler should start a
playhead-drag. TBD. but tempo-mapping is a special and rare operation.
