Fixed flicker when showing update window.
Fixed flicker when showing update window.

alamaison/winsparkle,Herve-M/winsparkle,artillery/winsparkle,bristol-instruments/winsparkle,dsuess/winsparkle,artillery/winsparkle,Herve-M/winsparkle,alamaison/winsparkle,dsuess/winsparkle,nickdademo/winsparkle,CaptainJackJJ/SmpUpdater,drizt/winsparkle,bristol-instruments/winsparkle,nickdademo/winsparkle,drizt/winsparkle,CaptainJackJJ/SmpUpdater