This can happen when a device is already connected
while Arodur is stating. The butler thread may activate it
(immediately post-engine), while the GUI thread tries
to do the same later when restoring state.
* correctly handle clicks on the immediate right or left of a beat line
* prefer Mid-Twist and End-Stretch terminology over Twist and Linear
* static-tempo vs ramped-tempo is orthogonal to mid- and end- drags (TODO)
Old code use the TempoMetric (Tempo + Meter) in effect at the old
location of the tempo/meter to compute the position of the edited tempo/meter,
using a BBT time from the dialog.
But this TempoMetric uses the very tempo/meter that we're editing!
So we have to use previous_tempo() or previous_meter() to construct
the relevant TempoMetric, and if it is the first tempo or meter, then
obviously it cannot move position at all.
* reserve "probe" to actually probe for devices
* use separate probe for libusb and MIDI port devices
* use "available" to check if surface can be used
* allow both methods to be NULL
* remove unused ControlProtocolDescriptor* argument
Most surface just return `true` for available.
In case of internal backends this allows to retrieve the
Device name for a given (hashed unique) port-name.
As opposed to "pretty-name" (which defaults to hw-port-name),
this cannot be changed by the user.
It is intended to be used when probing for control surfaces.
* in the 'fake_drag' case (dragging the playhead from the ruler), the
mouse events are delivered to the playhead during the drag so we need
to temporarily sensitize the playhead during that operation, then reset
the sensitivity via config
Historically, it was possible to grab the 1-pix-wide red line, and drag the playhead
In rare but annoying cases, the red playhead interferes with mouse clicks, because it is on top
De-sensitize the playhead by default, and provide a new config var for those who want the old operation
