TRUE and
the entire widget is redrawn on every size change. If your widget
leaves the upper left unchanged when made bigger, turning this
setting off will improve performance.gtkWidgetSetRedrawOnAllocate(object, redraw.on.allocate)objectredraw.on.allocateTRUE, the entire widget will be redrawn
when it is allocated to a new size. Otherwise, only the
new portion of the widget will be redrawn.NO_WINDOW widgets setting this flag to FALSE turns
off all allocation on resizing: the widget will not even redraw if
its position changes; this is to allow containers that don't draw
anything to avoid excess invalidations. If you set this flag on a
NO_WINDOW widget that does draw on widget->window,
you are responsible for invalidating both the old and new allocation
of the widget when the widget is moved and responsible for invalidating
regions newly when the widget increases size.