Implement correct event sink boilerplate for SpinButton
Implement correct event sink boilerplate for SpinButton

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