diff --git a/src/Lumper.UI/App.axaml.cs b/src/Lumper.UI/App.axaml.cs
index 22bf68a3..e007fa9d 100644
--- a/src/Lumper.UI/App.axaml.cs
+++ b/src/Lumper.UI/App.axaml.cs
@@ -1,27 +1,34 @@
-using Avalonia;
-using Avalonia.Controls.ApplicationLifetimes;
-using Avalonia.Markup.Xaml;
-using Lumper.UI.ViewModels;
-using Lumper.UI.Views;
-
-namespace Lumper.UI;
-
-public class App : Application
-{
-    public override void Initialize()
-    {
-        AvaloniaXamlLoader.Load(this);
-    }
-
-    public override void OnFrameworkInitializationCompleted()
-    {
-        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime
-            desktop)
-            desktop.MainWindow = new MainWindow
-            {
-                DataContext = new MainWindowViewModel()
-            };
-
-        base.OnFrameworkInitializationCompleted();
-    }
-}
+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Markup.Xaml;
+using Lumper.UI.ViewModels;
+using Lumper.UI.Views;
+
+namespace Lumper.UI;
+
+public class App : Application
+{
+    public override void Initialize()
+    {
+        AvaloniaXamlLoader.Load(this);
+    }
+
+    public override void OnFrameworkInitializationCompleted()
+    {
+        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime
+            desktop)
+        {
+            desktop.MainWindow = new MainWindow
+            {
+                DataContext = new MainWindowViewModel()
+            };
+
+            if (desktop.Args?.Length > 0)
+            {
+                ((MainWindowViewModel)desktop.MainWindow.DataContext!).LoadBsp(desktop.Args[0]);
+            }
+        }
+
+        base.OnFrameworkInitializationCompleted();
+    }
+}
diff --git a/src/Lumper.UI/Views/MainWindow.axaml.cs b/src/Lumper.UI/Views/MainWindow.axaml.cs
index f299b21d..db2cc3a7 100644
--- a/src/Lumper.UI/Views/MainWindow.axaml.cs
+++ b/src/Lumper.UI/Views/MainWindow.axaml.cs
@@ -1,51 +1,74 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Linq;
-using Avalonia.Controls;
-using Avalonia.Input;
-using Lumper.UI.ViewModels;
-
-namespace Lumper.UI.Views;
-
-public partial class MainWindow : Window
-{
-    public MainWindow()
-    {
-        InitializeComponent();
-
-        AddHandler(DragDrop.DragOverEvent, DragOver);
-        AddHandler(DragDrop.DropEvent, Drop);
-    }
-
-    private async void Window_OnClosing(object? sender, CancelEventArgs e)
-    {
-        if (DataContext is not MainWindowViewModel model)
-            throw new ArgumentOutOfRangeException();
-        await model.OnClose(e);
-    }
-
-    private void DragOver(object? sender, DragEventArgs e)
-    {
-        e.DragEffects = DragDropEffects.Link;
-
-        var names = e.Data.GetFileNames() ?? new List<String>();
-
-        if (!e.Data.Contains(DataFormats.FileNames) || !names.FirstOrDefault("").ToLower().EndsWith(".bsp"))
-            e.DragEffects = DragDropEffects.None;
-    }
-
-    private void Drop(object? sender, DragEventArgs e)
-    {
-        if (e.Data.Contains(DataFormats.FileNames))
-        {
-            var names = e.Data.GetFileNames() ?? new List<String>();
-            var target = names.FirstOrDefault("");
-
-            if (!target.ToLower().EndsWith(".bsp"))
-                return;
-
-            ((MainWindowViewModel)DataContext!).LoadBsp(target);
-        }
-    }
-}
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Linq;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Input;
+using Lumper.UI.ViewModels;
+
+namespace Lumper.UI.Views;
+
+public partial class MainWindow : Window
+{
+    public MainWindow()
+    {
+        InitializeComponent();
+
+        AddHandler(DragDrop.DragOverEvent, DragOver);
+        AddHandler(DragDrop.DropEvent, Drop);
+    }
+
+    private async void Window_OnClosing(object? sender, CancelEventArgs e)
+    {
+        if (DataContext is not MainWindowViewModel model)
+            throw new ArgumentOutOfRangeException();
+        await model.OnClose(e);
+    }
+
+    private void DragOver(object? sender, DragEventArgs e)
+    {
+        e.DragEffects = DragDropEffects.Link;
+
+        var names = e.Data.GetFileNames() ?? new List<String>();
+
+        if (!e.Data.Contains(DataFormats.FileNames) || !names.FirstOrDefault("").ToLower().EndsWith(".bsp"))
+            e.DragEffects = DragDropEffects.None;
+    }
+
+    private void Drop(object? sender, DragEventArgs e)
+    {
+        if (e.Data.Contains(DataFormats.FileNames))
+        {
+            var names = e.Data.GetFileNames() ?? new List<String>();
+            foreach (string target in names)
+            {
+                if (!target.ToLower().EndsWith(".bsp"))
+                    continue;
+
+                if (((MainWindowViewModel)DataContext!).BspModel == null)
+                {
+                    // if nothing is open, open it.
+                    ((MainWindowViewModel)DataContext!).LoadBsp(target);
+                }
+                else
+                {
+                    // Otherwise, open a brand new Lumper instance with it.
+                    string? mainModuleFileName = Process.GetCurrentProcess().MainModule?.FileName;
+                    if (mainModuleFileName == null)
+                        return;
+
+                    string? executablePath = mainModuleFileName;
+                    ProcessStartInfo startInfo = new ProcessStartInfo()
+                    {
+                        ArgumentList = { $"\"{target}\"" },
+                        FileName = executablePath,
+                    };
+
+                    Process.Start(startInfo);
+                }
+            }
+        }
+    }
+}