The popstate listener always called _navGoBack(), but both Back and Forward fire
popstate — so Forward was treated as Back and never restored the page you came from.
_navGoBack also pushState()'d on every back, which wiped the browser's forward stack
entirely.
Route all history through the History API: navigate() pushes a state (nsIdx) only on
genuine new navigation; popstate now applies whichever entry the browser moved to via
_navOnPopState(state.nsIdx), covering Back AND Forward with no pushState in the
handler. In-app back buttons / Backspace go through history.back() so there's a single
path and the browser stack stays in sync. NowPlaying overlays still close first on a
back press.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
HoneyandClaude Opus 4.8
79100c5321