[MU4 Issue] When selecting first note there is an appreciable time lag before it sounds and is highlighted

[rgreen5]

Describe the bug

If you have nothing selected, then click on a notehead with the mouse, there is a short, but appreciable, delay before the note sounds and is highlighted. However, now that a note is selected and you click on another note, the delay disappears and the new note sounds and is highlighted virtually instantaneously. If you clear the selection and try the same thing again, exactly the same thing happens.

By contrast, if you select any other, non-sounding, element there is no delay in highlighting.

There was never any delay between clicking on a note and it sounding or highlighting in MS3.

To Reproduce

1. Open the attached score example.
   delayed_note.zip
2. With nothing selected, click on a notehead.
3. Now, with the notehead selected, click on another notehead (releasing the previous notehead).
   RESULT: In step 2, there is a short, but appreciable delay. But virtually no delay in step 3.
4. Now export a musicXML file and do the same experiemnt in MS3.
   RESULT: There is no delay at any stage.

Expected behavior

When you click on a notehead, it should sound and be highlighted instantaneously – just as it did in MS3. There should not be the difference in time lag between the cases shown above in MS4.

Platform information

OS: Linux Mint 20.1, Arch.: x86_64, MuseScore version (64-bit): 4.0.0-223110421, revision: github-musescore-musescore-ff5a8c7

Intel Pentium CPU 2020M @ 2.40GHz × 2 / 3.7 Gb. RAM

[Tantacrul]

We have a new build with a lot of performance improvements which will be merged soon. That may conclusively solve this.

In the meantime, it would be good to find out whether this problem is still occurring, since the issue is two weeks old and there have been a lot of changes in the meantime to performance. Thanks!

[rgreen5]

OS: Linux Mint 20.1, Arch.: x86_64, MuseScore version (64-bit): 4.0.0-223270405, revision: github-musescore-musescore-46ce488

Issue still present here.

[rgreen5]

OS: Linux Mint 20.1, Arch.: x86_64, MuseScore version (64-bit): 4.0.2-230460504, revision: github-musescore-musescore-a36e598

Some more observations:

1. Click on a note in the demonstration score
   RESULT: Appreciable sound lag from key press to audio.
2. Click on another note.
   RESULT: The sound lag is now negligible
3. Clear the selection by clicking on a blank space on the score paper. Then click on a note again.
   RESULT: The sound lag appears again.
4. Shift + click on another note to create a range selection.
   RESULT: There is a lag between the key press and the selection being highlighted.

[bluebear94]

I just discovered that MuseScore 4 has a profiler and tried running it after selecting notes a few times. Unfortunately, I can’t find a way to copy the text from the profiler, so a screenshot will have to do.

It might be that most of the delay is coming from updating the Properties panel.

[bluebear94]

As of MS 4.2.1, the lag at least occurs only if the Properties panel is visible (as opposed to being opened but not on the current tab).