In some cases, it might make sense for blur (focus leaving the <popup>) to trigger light dismiss. For example, if the <popup> is the menulist for a <selectmenu>, when the list is opened, it is focused, and tabbing out feels like it should close. However, in most other cases, it seems like this behavior would likely be confusing. In particular, because the <popup> is not focused by default (without autofocus or delegatesfocus), it feels especially weird that tabbing over to <popup> and then leaving it should close it. But it came up in a discussion, so I thought I should raise it here. Perhaps it should be a light-dismiss trigger only if the <popup> is auto-focused?