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The menu opened but never appeared: it was absolutely positioned inside .copilot-tabs, whose overflow-x: auto clips on both axes, so the dropdown was cut off inside the tab strip. And once visible, every click would have landed on the transparent full-screen overlay (z-index 99) above the menu (z-index 20), closing it instead of choosing an entry. Anchor the menu to the + button with fixed positioning (the same escape the model dropdown gets from living outside any clipping container) and raise it to z-index 100, above the overlay it shares with the other pills.