It is possible to shrink a note to a point where it’s practically invisible. In addition, these micro-notes don’t play and if not removed, inhibit the play of any note placed on top of it. You can delete, but not resize the note if you use maximum zoom.
Is there any way to restrict how small (short) you can resize a midi note? They are easily detected as they create a dropout, but they are difficult to see when using a laptop.
The ability to resize a note to a minuscule size is more of a behavior than a bug, but the fact that it won’t play when shrinked, is definitely a bug.
Not as far as I know. Using snap-to-grid can help to avoid this, but that’s not a hard limit.
When using percussive mode, new notes are by default very short (IIRC 1/128th or shorter), this is entirely intentional.
You could switch the track to percussive mode (MIDI track header’s context menu > Note Mode > Percussive), and then delete the diamonds, which should be easily visible. Alternatively Region menu > MIDI > List editor might be handy.
Are you certain that the MIDI event is not sent to the synth? Check with “a-MIDI monitor” plugin.
What synth are you using? It’s more likely that the note is too short to be audible or the note-off arrives early in the attack stage.