switchable-layout is a subclass of
simple-layout which displays only one of its children at a time, and provides functionality for switching the displayed child to one of the other children.
switchable-layout inherits most of its layout behavior from simple-layout as it only ever lays out one child at a time.
influences the initial size of the layout. When
nil the constraints of the switchable layout depend only on its currently visible child pane. Switching to a different child pane might cause the layout to resize. When
is non-nil, the constraints depend on all of the child panes, including those that are not visible. This might increase the time taken to create the switchable layout initially, but can prevent unexpected resizing later. The default value of
CAPI User Guide and Reference Manual (Macintosh version) - 3 Aug 2017