[Mac] fix initial SpinButton value
[Mac] fix initial SpinButton value

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