Where a menu or popover opened from a control should be portaled: the fullscreen element while the control is inside browser fullscreen, and its own document's body otherwise. A popup appended to the body is invisible while another element is fullscreen, so every kit overlay picks its container through this one helper as it opens.
pnpm dlx shadcn@latest add "https://pluginui.com/r/core-overlay-container.json"No files included in this item.