[#65] MailLogWindow: Fix initial loading

Elwig/Windows/PaymentVariantsWindow.xaml.cs

@@ -57,10 +57,10 @@ namespace Elwig.Windows {
                 .OrderBy(v => v.AvNr)
                 .Include(v => v.Season.Currency)
                 .ToListAsync());
-            Update();
+            await Update();
         }
 
-        private void Update() {
+        private async Task Update() {
             if (PaymentVariantList.SelectedItem is PaymentVar v) {
                 var locked = !v.TestVariant;
                 DeleteButton.IsEnabled = !locked;
@@ -278,8 +278,8 @@ namespace Elwig.Windows {
             });
         }
 
-        private void PaymentVariantList_SelectionChanged(object sender, SelectionChangedEventArgs evt) {
-            Update();
+        private async void PaymentVariantList_SelectionChanged(object sender, SelectionChangedEventArgs evt) {
+            await Update();
         }
 
         private async void AddButton_Click(object sender, RoutedEventArgs evt) {