[MU4 Issue] Lagging when working with large scores

[JasperJelmer]

If you are working with a large score for around 15 minutes. Musescore starts lagging and starts claiming it doesn't react. Especially when you have saved the file

Steps to reproduce the behavior:

1. Open any large score (for instance a large string orchestra with a lot of woodwinds, brass, and percussion)
2. Work on it for 5-10 minutes on the score
3. Save the score
4. Continue working on the score
5. Eventually (with different timing) it will start to claim it's not working and starts to lag on every command you put in.

Expected behavior
Simply that it doesn't become slower the longer you work (very basic, I know)

Platform information

• Asus TUF gaming laptop running Windows 11

Additional context
A possible flaw is that I opened old musescore files. Saved on musescore 3.6.2 and opened them with musescore 4 (beta)

[DaddyLudwig]

I'm also getting this with my Solo Flute Arrangements file, and after a while of lagging, it crashes and I have to open it back up again. 1 instrument, over 1000 measures. And that was originally made in Musescore 4.

[JasperJelmer]

Today I started a new score large score on musescore 4, same problem. So I do not think, opening an older saved musescore file might be the core of the problem.

[oktophonie]

This sounds very reminiscent of #13133 (and #14057). It seems that certain UI operations are causing the problem - possibly due to memory leaks, as suggested. It would be good to narrow down particular panels/boxes that seem to be likely culprits.

[marczellm]

My suspicion is that the saving of the large score takes a long time and freezes the UI, but also there are autosaves happening in the background that do the same thing.