ResultWindow.axaml.cs

@@ -230,7 +230,20 @@ public partial class ResultWindow : Window, INotifyPropertyChanged
 
     private void BtnShowSelected_OnClick(object? sender, RoutedEventArgs e)
     {
-        // once upon a time, there was a feature like this
+        if (LbResults.SelectedItems.Count > 0)
+        {
+            var selectedPersons = LbResults.SelectedItems
+                .Cast<ResultItem>()
+                .Select(x => x.Person)
+                .ToList();
+
+            if (selectedPersons.Count == 0)
+                return;
+
+            var preview = new PreviewWindow(selectedPersons);
+            preview.Show();
+           
+        } 
     }
 
     private void BtnExecuteFilter_OnClick(object? sender, RoutedEventArgs e)