UIW: avoid to refresh uilayer when not needed

Change-Id: Id2cbfbd948b137a1aa0632902c4481eb8ea008a2
UIW: fix bug in setting items in combo

Change-Id: I881a6a06e38ef28c808123cc63b175c9fe09b024
UIW: center correctly dialog on parent

Change-Id: I5ba1dc4d3e55778bbddfdab1115b00688f2eecae