A container that arranges its child controls vertically and wraps them around at the borders. A variant of [FlowContainer] that can only arrange its child controls vertically, wrapping them around at the borders. This is similar to how text in a book wraps around when no more words can fit on a line, except vertically. $DOCS_URL/tutorials/ui/gui_containers.html The horizontal separation of children nodes. The vertical separation of children nodes.