CardMenu entries declare a submenu as data (`submenu: [ {label, icon,
action} ]`); the row builds a child CardMenu on first use, opens it when
the pointer rests on the entry (or clicks it), and closes it when the
pointer moves to another entry. While either menu is hovered the pair
stays open; leaving both for 350 ms, pressing Escape or clicking outside
closes both. Picking in the child closes the parent too.
The track row, the Popular Tracks row and the player bar's "+" menu
declare their Copy entries this way instead of re-opening a second
CardMenu at the row's saved click position.
cc
vicrodh
7f609a55e5