Z-index for content that is portalled OUT of a popover and must still render over it — a Radix
dropdown, menu, or select opened from inside PopoverContent.
Radix portals such content to document.body rather than nesting it inside the popover, so the
two become stacking SIBLINGS: the popover's own Z_INDEX_ABOVE_DOCK competes directly with
whatever the portalled child asks for, and anything lower renders behind the popover it belongs
to. Must therefore stay above Z_INDEX_ABOVE_DOCK and below Z_INDEX_FIRST_RUN, which
gates the whole app. Pinned by z-index.test.ts.
Note this is only needed because Z_INDEX_ABOVE_DOCK sits so high; see its own doc.
Z-index for content that is portalled OUT of a popover and must still render over it — a Radix dropdown, menu, or select opened from inside
PopoverContent.Radix portals such content to
document.bodyrather than nesting it inside the popover, so the two become stacking SIBLINGS: the popover's own Z_INDEX_ABOVE_DOCK competes directly with whatever the portalled child asks for, and anything lower renders behind the popover it belongs to. Must therefore stay above Z_INDEX_ABOVE_DOCK and below Z_INDEX_FIRST_RUN, which gates the whole app. Pinned byz-index.test.ts.Note this is only needed because Z_INDEX_ABOVE_DOCK sits so high; see its own doc.