Fixed issue where multiple threads were attempting to modify search result list (#761)

* Fixed issue where multiple threads were attempting to modify search result list

* Fixed race condition

src/App/Pages/Vault/CiphersPage.xaml.cs

@@ -75,7 +75,7 @@ namespace Bit.App.Pages
             {
                 return;
             }
-            _vm.Search(e.NewTextValue, 500);
+            _vm.Search(e.NewTextValue, 200);
         }
 
         private void SearchBar_SearchButtonPressed(object sender, EventArgs e)

src/App/Pages/Vault/CiphersPageViewModel.cs

@@ -77,7 +77,7 @@ namespace Bit.App.Pages
                 .GetValueOrDefault();
             if(!string.IsNullOrWhiteSpace((Page as CiphersPage).SearchBar.Text))
             {
-                Search((Page as CiphersPage).SearchBar.Text, 500);
+                Search((Page as CiphersPage).SearchBar.Text, 200);
             }
         }
 
@@ -110,16 +110,19 @@ namespace Bit.App.Pages
                     }
                     catch(OperationCanceledException)
                     {
-                        ciphers = new List<CipherView>();
+                        return;
                     }
                 }
                 if(ciphers == null)
                 {
                     ciphers = new List<CipherView>();
                 }
-                Ciphers.ResetWithRange(ciphers);
+                Device.BeginInvokeOnMainThread(() =>
-                ShowNoData = searchable && Ciphers.Count == 0;
+                {
-                ShowList = searchable && !ShowNoData;
+                    Ciphers.ResetWithRange(ciphers);
+                    ShowNoData = searchable && Ciphers.Count == 0;
+                    ShowList = searchable && !ShowNoData;
+                });
             }, cts.Token);
             _searchCancellationTokenSource = cts;
         }