> on Mac OS the left part of the menu bar (including the system menu) is drawn and managed by the current application IIRC it is not drawn by the application,

> on Mac OS the left part of the menu bar (including the system menu) is drawn and managed by the current application IIRC it is not drawn by the application, it's a system app that gets the focused (or rather, activated) app menu hierarchy as the app instructs through some IPC, but it's not the app process itself drawing there. The only part where an app actually can draw is on the right part, when one implements menu bar extras (which previously required hacks to inject into because the menubar extra API was severely limited, but IIUC now has a dedicated, managed API to replace the hacks)