actually now its usable

Kits/Views/ProperCollectionEditor.cs

@@ -0,0 +1,21 @@
+using System.Collections;
+using System.Windows;
+namespace Kits.Views;
+
+public partial class ProperCollectionEditor : Window
+{
+    public ProperCollectionEditor()
+    {
+        InitializeComponent();
+    }
+
+    private void ButtonAdd_OnClick(object sender, RoutedEventArgs e)
+    {
+        ((IList)DataContext).Add(Activator.CreateInstance(DataContext.GetType().GenericTypeArguments[0]));
+    }
+    private void ButtonDelete_OnClick(object sender, RoutedEventArgs e)
+    {
+        if (ElementsGrid.SelectedItem is { } item)
+            ((IList)DataContext).Remove(item);
+    }
+}