Merge pull request #43861 from allisonchou/SelectedItemChangeSignatureBug

Fix for selected item jumps out of view with long argument list in Change Signature

src/VisualStudio/Core/Def/Implementation/ChangeSignature/ChangeSignatureDialog.xaml.cs

@@ -230,6 +230,7 @@ private void MoveSelectionDown_Click(object sender, EventArgs e)
 
         private void Members_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
         {
+            Members.SelectedIndex = Members.Items.IndexOf(Members.CurrentItem);
             if (Members.SelectedIndex == -1)
             {
                 Members.SelectedIndex = _viewModel.GetStartingSelectionIndex();