--this way storedViews are reproduced only when
really needed. If an action has already produced
a storedView and no changes may have happen when
that storedView is used at all cases
--in the past a layout could draw more than
own icons in order to be identified. Now
things are simplified and at all cases ONLY ONE icon
is chosen for each layout based on criteria.
In all cases if the user has chosen a specific
icon for its layout that is respected for all
drawing cases.
--when Switch button is used exactly after the user
is choosing single mode, the layouts model mode is also
updated directly in order to be consistent with
user options