[WPF] Register listbox backend
[WPF] Register listbox backend

antmicro/xwt,cra0zy/xwt,mono/xwt,mminns/xwt,steffenWi/xwt,TheBrainTech/xwt,hamekoz/xwt,akrisiun/xwt,residuum/xwt,hwthomas/xwt,iainx/xwt,mminns/xwt,lytico/xwt,directhex/xwt,sevoku/xwt