Query parameter passed to the renderer. Present only on the main window, absent on every
secondary window, so the renderer can tell which chrome to draw — on Windows and Linux the main
window keeps the top-level menu and secondary windows do not. On macOS the top-level menu lives
in the OS-level menu bar, which is process-global and reachable from every window regardless of
this flag.
Fixed at window creation, which is a deliberate limitation: it cannot describe a window becoming
the main one later. PT-4278's window-manager service is the durable answer; replace this when it
lands.
Query parameter passed to the renderer. Present only on the main window, absent on every secondary window, so the renderer can tell which chrome to draw — on Windows and Linux the main window keeps the top-level menu and secondary windows do not. On macOS the top-level menu lives in the OS-level menu bar, which is process-global and reachable from every window regardless of this flag.
Fixed at window creation, which is a deliberate limitation: it cannot describe a window becoming the main one later. PT-4278's window-manager service is the durable answer; replace this when it lands.