Multi instance, tab handling

src/GuiApp/Avalonia/FileTime.GuiApp.App/Views/SettingsWindow.axaml.cs

@@ -0,0 +1,13 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace FileTime.GuiApp.App.Views;
+
+public partial class SettingsWindow : Window
+{
+    public SettingsWindow()
+    {
+        InitializeComponent();
+    }
+}