Added extra handling for linux screens

MainWindow.axaml.cs

@@ -1,11 +1,13 @@
 using System;
 using System.ComponentModel;
+using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
 using System.Reactive.Linq;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
+using Avalonia.Platform;
 
 namespace SimpleNote;
 
@@ -15,7 +17,19 @@ public partial class MainWindow : Window
     private PixelRect? screen;
     public MainWindow()
     {
+        if (Screens.Primary == null)
+        {
+            Screen max = Screens.All[0];
+            for (int i = 0; i < Screens.ScreenCount; i++)
+            {
+                if (Screens.All[i].Bounds.Width > max.Bounds.Width) max = Screens.All[i];
+            }
+
+            screen = max.WorkingArea;
+        }
+        else
             screen = Screens.Primary?.WorkingArea;
+
         if (screen == null)
         {
             Console.WriteLine("No screen available.");
@@ -80,6 +94,7 @@ public partial class MainWindow : Window
         if (width == 55) width -= 5;
         
         this.Width = width;
+        if(!System.OperatingSystem.IsLinux())   // Screenpositionhandling on Hyprland/Wayland/X11 is different
             this.Position = new PixelPoint((int)((screen.Value.Width - width) / 2), 10);
     }