fix null reference error for refresh button
fix null reference error for refresh button

WasimAhmad/Serenity,dfaruque/Serenity,volkanceylan/Serenity,linpiero/Serenity,volkanceylan/Serenity,dfaruque/Serenity,rolembergfilho/Serenity,dfaruque/Serenity,linpiero/Serenity,rolembergfilho/Serenity,volkanceylan/Serenity,dfaruque/Serenity,volkanceylan/Serenity,linpiero/Serenity,TukekeSoft/Serenity,rolembergfilho/Serenity,WasimAhmad/Serenity,rolembergfilho/Serenity,WasimAhmad/Serenity,linpiero/Serenity,TukekeSoft/Serenity,WasimAhmad/Serenity,TukekeSoft/Serenity,volkanceylan/Serenity,dfaruque/Serenity,WasimAhmad/Serenity,linpiero/Serenity,rolembergfilho/Serenity,TukekeSoft/Serenity