QOpenGLWidget VSync Causing Issue With NSDistributedNotificationCenter

[jgvw]

I am having an issue on macOS with QOpenGLWidget and VSync, that does not occur with the native NSOpenGLView. NSNotifications sent from another process using NSDistributedNotificationCenter are not consistently processed unless user input is occurring (mouse or keyboard).

Here is a link to some minimal test projects I put together that demonstrate the issue. I'm not sure whether there is something I'm doing wrong, or if there is a bug in Qt's macOS OpenGL handling somewhere, or if there's a bug in the macOS OpenGL implementation that for whatever reason isn't being hit with the native widget.

I know this is a long shot as it's probably a very rare interaction, but I'd greatly appreciate any ideas anyone has for how to investigate this further, or who to talk to about getting this resolved.

Edit: I created a bug report here: https://bugreports.qt.io/browse/QTBUG-106568