macOS: Song Editor patterns won't snap to grid

[tresf]

Bug Summary

Something's very wrong on macOS with the song editor, the patterns won't snap to grid.

Since the default snapping behavior is common for composers, this renders LMMS mostly useless for users relying on this behavior. This is a major detriment to any macOS user.

Tested:

• 🚫 broken: macOS 10.16 (beta)
• 🚫 broken: macOS 10.14

Oddly, it works when using the build of LMMS targeted at older platforms (<=10.8, but not the one targeted at >=10.13)

• GOOD: 1.2.0 (10.8 build)
  

• BAD: 1.2.0, 1.2.2 (10.13 build)
  

Known Workarounds

None, except to revert to LMMS 1.2.0 targeted at macOS <=10.8. At time of writing this, this older version works fine with newer macOS versions (e.g. 10.14, 10.15, 10.16 beta).

[PhysSong]

I can confirm it. Strangely, if I build LMMS 1.2.2 on macOS 10.15, everything works fine there.

[tresf]

@PhysSong I assume it's confused about a Qt::ControlModifier (or Meta) key somewhere (which should help us find an upstream bug report), but I don't know where this flag is checked on stable. Any pointers?

[PhysSong]

it's confused about a Qt::ControlModifier (or Meta) key somewhere

I think it's TrackContentObjectView::draggedTCOPos() for master and TrackContentObjectView::mouseMoveEvent() for stable-1.2.
BTW, this might be some compatibility issue between different OS versions and/or compiler versions, like #5582.

[PhysSong]

I've created macOS 10.14+ build with Qt 5.15.0 and tested it. It seems to fix both this and #5582. I will upload it to the release page and add a warning.

[tresf]

@PhysSong thanks for that. I can confirm that it's working fine on 10.16 (beta) as well. Shall we close these both as upstream ?

[fbbdev]

Hello, the same problem is still happening on MacOS 10.13.6 with the 10.13+ build. I've just redownloaded and tested it to be sure. I'm not an expert with MacOS development so I'm not sure whether it is safe to test the 10.14+ build on my 10.13 machine.

[tresf]

I'm not sure whether it is safe to test the 10.14+ build on my 10.13 machine.

It won't harm to try. If it's incompatible it will simply fail to run.

[fbbdev]

In fact it refuses to run, says it is incompatible with my system.