// I suggest that when this is no longer experimental, rather than all these #ifdef's,
// this be done by factoring, i.e., add two subclasses to MixerTrackCluster,
// MixerNoteTrackCluster and MixerWaveTrackCluster, such that all the common
// code is in the parent, and these #ifdef's are only around
// MixerNoteTrackCluster rather than sprinkled throughout MixerTrackCluster.
This bug was introduced in commit 10680 and caused in MixerTrackCluster::UpdatePan(), by using USE_MIDI (which is on in releases) instead of EXPERIMENTAL_MIDI_OUT (which is off). It checked whether a NoteTrack pointer was NULL, and if not, hid the Pan slider (not used in NoteTrack clusters). But an invalid pointer is non-null, so was causing the Pan slider to always be hidden.