The notification dropdown was at z-index: 100, well below fullscreen
terminals (1000), modal overlays (1000), and dialog overlays (1000).
Because .notification-center creates a stacking context with no explicit
z-index, the dropdown was trapped behind any of those overlays and
became unclickable.
- Set .notification-center z-index to 9999 so it competes above all
other overlays in the root stacking context.
- Set .notification-dropdown z-index to 9999 for consistency.
Quality gates: tsc --noEmit (pass), build (pass)
Developer
597cfb9573