Currently the MIDI Actions dialogs are entirely non-functional.
Steps to reproduce:
1) Add a note
2) Add a staccato and select the staccato dot
3) In the inspector panel, at the bottom, there will be a "properties" button. Select "properties".
4) A dialog box will appear. At the bottom of the dialog is a section titled "MIDI Action" which is entirely unpopulated and has no function.
Here are the steps to reproduce a related by slightly different issue:
1) Add two notes of different pitches
2) Add a slur to connect the two notes. Select the slur
3) In the inspector panel, you will see that there is no "properties" button. This should be consistent between all articulations, however it is not.
Here are the steps to reproduce another related, but slightly different issue:
1) Add staff text, such as "arco"
2) Ensure the text is selected
3) Select the "properties" button in the inspector
4) Select the tab "MIDI Actions"
5) Again, the bottom portion of this tab is entirely non-functional
What I believe the correct behaviour should be is:
Users should be able to select a midi note (including the ability to specify velocity), CC value or program change message that is triggered by the specified text or articulation. Ideally MIDI actions could be triggered by text and articulations (as mentioned) but also as a property of any element on the page, such as dynamics, or a double barline at the start of a new section, for example.
In the case of articulations, it should also be possible to specify a secondary note, CC or program change message that is triggered at "note-off". For example, this would allow a keyswitch to be sent to an external device for a "staccato" note, but to ensure that following notes are performed with a "normal" or default articulation.
In an ideal situation, it would be great if this midi action could be set to be sent out a few milliseconds before the text, note, or articulation. This "look-ahead" time should be user adjustable.