fix fade out animation glitch per @allu22 in #13
fix fade out animation glitch per @allu22 in #13

dmiedema/calloutview,mapbox/SMCalloutView,XBeg9/calloutview,Suninus/calloutview,Petvetbook/calloutview,Aiwis/calloutview,Suninus/calloutview,u10int/calloutview,XBeg9/calloutview,Petvetbook/calloutview,mapbox/SMCalloutView,u10int/calloutview,nfarina/calloutview,dmiedema/calloutview,Aiwis/calloutview,nfarina/calloutview