[WPF] Paned sizing improvements
[WPF] Paned sizing improvements

Don't constraint the height of panels in horizontal layouts
(and width on vertical layouts)

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