cleanup isbusy on page disappearing

src/App/Controls/ExtendedContentPage.cs

@@ -1,5 +1,4 @@
 using Bit.App.Abstractions;
-using System;
 using Xamarin.Forms;
 using XLabs.Ioc;
 
@@ -37,5 +36,11 @@ namespace Bit.App.Controls
             googleAnalyticsService.TrackPage(GetType().Name);
             base.OnAppearing();
         }
+
+        protected override void OnDisappearing()
+        {
+            IsBusy = false;
+            base.OnDisappearing();
+        }
     }
 }