Drag handle disappearance

[Monospace-V]

Closest similar issue: #6330 where it is mentioned the drag handle disappears sometimes.

Bug Summary

Drag handle disappears sometimes, on some specific projects. One of the triggers, in some cases, is renaming a track.

Steps to reproduce

1603bugcheck.zip
Download the above zipped folder, and extract the file. It works only in 1.3 alpha.

1. Open the Beat/Bassline editor.
2. Rename any track there.

Expected behavior

Track gets renamed and track drag handles (dotted part of track for dragging) continue to stay visible

Actual behavior

Track gets renamed and track drag handles cease to exist

Screenshot

Video:

1603bugcheck.-.LMMS.1.3.0-alpha.1.169+g537ad1d38.2022-03-17.14-42-15.mp4

Affected LMMS versions

1.3 alpha

This bug is tricky to reproduce in general, and easier to reproduce with the file.

[PhysSong]

Bug confirmed. Some conditions should be met to reproduce this bug:

• The editor must be able to be scrolled vertically
• Enter/Return key should be pressed after renaming

In 1.2, there is a small gap between the right edge of the window and the end of the note area.

1.3 doesn't have such a gap.

I'm sure this is related to the bug, and the scroll area in TrackContainerView is somehow related.

[PhysSong]

I found that #5102 caused the issue and also #6330.
When the vertical scroll bar is visible, the width of TrackContainerView::m_scrollArea->widget() plus the width of the scroll bar becomes larger than the width of TrackContainerView, which make the scroll area vertically scrollable.

Note, if #5101 had been merged instead, this bug wouldn't happen. Instead, there will be a small visual artifact in the BB editor(now renamed to pattern editor):

2022-03-19.16-05-19.mp4

[allejok96]

Instead, there will be a small visual artifact in the BB editor(now renamed to pattern editor)

One could argue that having the last step of the pattern hidden behind the scrollbar (current behavior) is an artifact.

[musikBear]

There is no bug if song-editor is maximized.
The bug only appear in windowed mode: