A grow-box-spacer-pane% object is intended for use as a lightweight spacer in the bottom-right corner of a frame, rather than as a container. On older version of Mac OS, a grow-box-spacer-pane% has the same width and height as the grow box that is inset into the bottom-right corner of a frame. On Windows, Unix, and recent Mac OS, a grow-box-spacer-pane% has zero width and height. Unlike all other container types, a grow-box-spacer-pane% is unstretchable by default.
See pane% for information on initialization arguments.