plist.add (ARDOUR::Properties::start, start);
plist.add (ARDOUR::Properties::length, 1);
+ /* Just above we're setting this nascent region's length to 1. I think this
+ is so that the RegionView gets created with a non-zero width, as apparently
+ creating a RegionView with a zero width causes it never to be displayed
+ (there is a warning in TimeAxisViewItem::init about this). However, we
+ must also set length_beats to something non-zero, otherwise the frame length
+ of 1 causes length_beats to be set to some small quantity << 1. Then
+ when the position is set up below, this length_beats is used to recompute
+ length using Tempo::framepos_plus_bbt, which is slightly innacurate for small
+ beats values (see comment in Tempo::framepos_plus_bbt) [mostly because
+ it converts floating point beats to bars, beats and integer ticks]. The upshot
+ of which being that length gets set back to 0, meaning no region view is ever
+ seen, meaning no MIDI notes during record (#3820).
+ */
+ plist.add (ARDOUR::Properties::length_beats, 1);
plist.add (ARDOUR::Properties::name, string());
plist.add (ARDOUR::Properties::layer, 0);