Multiple bugs related to tremolos between notes in MS 4.1

[LupusCaeruleus]

Issue type

Engraving bug, UI bug

Bug description

This issue consists of 5 issues related to tremolos between notes.

OS: Windows 10 Version 2009 or later, Arch.: x86_64, MuseScore version (64-bit): 4.1.0-231731239, revision: github-musescore-musescore-7d15ce0

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1. Our good old friend

When opening a score saved in MS 3.x, tremolos between notes are rendered incorrectly, until a "redraw" update is triggered.

Steps to reproduce:

1. Download and open the file → Sample File - Jupiter The Planets.zip
2. See the bars of Piano I on page 4.
3. Do anything that updates the score, the notes will be fixed.

2023-06-25.22-19-55.mp4

Regression:
No. Also present in MS 4.0.

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2. The 3rd style of the tremolo beam is identical to the 2nd one

Steps to reproduce:

1. Select a tremolo between two quarter notes (or greater duration), click the 3rd style in the properties panel.
2. See the result.

2023-06-25.22-24-29.mp4

Regression:
Yes. Works in MS 3.x.

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3. Sometimes the tremolo beam is forced horizontal

I have not figured out the conditions that trigger this bug, but it only seems to happen between a chord and another chord/note.

Steps to reproduce:

1. Create the tremolos below.
2. Compare the results.

Also notice the incorrectly forced-horizontal tremolo beams in the screenshots from bugs I. and V. They should behave exactly the same as normal note beams.

Regression:
Yes. Works in MS 3.x.

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4. Adjusting the angle of a tremolo beam then changing the stem direction will completely ruin the rendering

Manually adjusting the angle of a tremolo beam then changing the stem direction twice will cause the stems fail to be drawn, with the tremolo beam misplaced.

Steps to reproduce:

1. Select a tremolo beam, use any of its three square "control points" to adjust its angle or positioning.
2. Press X twice.
3. See the result.
4. Arbitratily Press X and the Reset stem direction button in the properties panel. See the result.

2023-06-25.23-11-06.mp4

5. And if you are lucky enough, you may even get this eventually.

2023-06-25.23-15-03.mp4

6. Finally, save the file and re-open it. All tremolo beams will return to normal, along with any of your modifications. So, it is technically impossible to save the adjustments of angles and positioning of tremolo beams.

Regression:
No. It is impossible to adjust tremolo beams independently before 4.1.

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5. Using Ctrl+click in Note input mode will allow user to add notes in between the tremolo notes

Steps to reproduce:

1. Select a beam with tremolo between notes, enter note input mode, press and hold Ctrl key, then click.
2. New notes are inserted in between the tremolo notes rather than after them.

2023-06-25.23-28-48.mp4

3. Save the file and re-open it. The tremolos will be fixed, by re-grouping the new-added notes.

Regression:
No.

Steps to reproduce

See above.

Screenshots/Screen recordings

No response

MuseScore Version

4.1.0-231731239

Regression

It varies.

Operating system

Windows 10

Additional context

No response

[oktophonie]

I've spun off the UI bug in here (which was numbered 4.i) to a separate issue: #18312
Everything that remains should be addressed by #18259