A sheet is said to be enabled when its parent has provided space for it. If a sheet and its ancestors are enabled and grafted (q.v.), then the sheet will be visible if it occupies a portion of the graft region that is not clipped (q.v.) by its ancestors or their siblings.
An interface element state that means that a menu item, button, and so on, can be used in the current context (that is, it responds to keyboard or cursor/mouse input).