With the AI chat docked at 1440px, a board with many canvas controls (XIAO:
display + camera + mic + scope) wrapped the strip INSIDE the header — the
canvas controls orphaned on a second line next to a black hole — because
the drop-to-own-bar fallback fired on media-query thresholds (1040 / 1060 /
1400px by chat state) that were only right for one board's strip width.
AppHeader now measures: natural single-row width of the strip (each zone at
its content width) against the room left next to the brand + menus, and
sets app-header--strip-below when it does not fit. Always measured in the
inline layout (class removed, measured, restored before paint) so the
below-state's margins and uncollapsed labels never bias the decision, and
there is nothing to oscillate. Re-measured via ResizeObserver on the strip
host, the brand block and the zones (plus a MutationObserver for the
portaled canvas controls), deferred a frame so a toggle never re-enters
delivery. The three media-query blocks collapse into one class rule; a
1000px window without the chat now keeps one row when the collapsed strip
fits, instead of being forced to two.
David Montero