Made HyperLink focusable

Wino.Mail/Dialogs/SignatureEditorDialog.xaml

@@ -241,6 +241,8 @@
                 <AppBarButton
                     x:Name="LinkButton"
                     Width="48"
+                    Click="LinkButtonClicked"
+                    FrameworkElement.AllowFocusOnInteraction="True"
                     Label="Add HyperLink"
                     ToolTipService.ToolTip="Add HyperLink">
                     <AppBarButton.Flyout>

Wino.Mail/Dialogs/SignatureEditorDialog.xaml.cs

@@ -258,8 +258,9 @@ namespace Wino.Dialogs
         private async void LinkButtonClicked(object sender, RoutedEventArgs e)
         {
             // Get selected text from Quill.
+            HyperlinkTextBox.Text = await TryGetSelectedTextAsync();;
 
-            HyperlinkTextBox.Text = await TryGetSelectedTextAsync();
+            HyperlinkFlyout.ShowAt(LinkButton);
         }
 
         private async Task UpdateEditorThemeAsync()