- Menu popups (menu bar, context menus, submenus) now occlude hover
beneath them via a BlockMouse hitbox, so items under an open popup no
longer stay highlighted.
- Menu bar dropdowns anchor to the opened title's bottom-left (local
anchoring) instead of the raw pointer position plus a fixed offset;
submenus are absolute children of the popup with separator-aware row
alignment.
- Selected timeline clips render one luma notch darker so the
selection is visible against the green clip body.