Make sure I didn't affect the plugin-related bug with my removal of the
m_pluginMapper QSignalMap strategy. You were specifically deleting m_PluginMapper on the MacOS in MainWindow for modal dialog reasons (according to the comments in the code). But m_pluginMapper no longer exists, so I removed the code to delete it on MacOS. Perhaps there's something else that needs deleting instead RE plugin actions/objects? All connects/disconnects are still done as before, the QSignalMap object just went away.
EDIT: Oops. it appears the m_pluginMapper object is still defined in MainWindow.h. I'll need to get rid of that, but I can't imagine it would cause any problems as is?