diff --git a/Kernel.cs b/Kernel.cs
index 9d86523..fd9801b 100644
--- a/Kernel.cs
+++ b/Kernel.cs
@@ -32,7 +32,10 @@ public class Kernel : Sys.Kernel
             new ViewProcessLogs()
         ]);
 
+        Sys.Graphics.Canvas canvas = Sys.Graphics.FullScreenCanvas.GetFullScreenCanvas();
+
         Sys.Mouse.MouseManager.Initialize();
+        Sys.Mouse.MouseManager.SetScreenSize((int)canvas.Mode.Width, (int)canvas.Mode.Height);
         Sys.Keyboard.KeyboardManager.Initialize();
     }
 
diff --git a/UI/GUI/Rendering/CanvasRenderSource.cs b/UI/GUI/Rendering/CanvasRenderSource.cs
index 19d5c2f..867b8a4 100644
--- a/UI/GUI/Rendering/CanvasRenderSource.cs
+++ b/UI/GUI/Rendering/CanvasRenderSource.cs
@@ -44,8 +44,11 @@ public sealed class CanvasRenderSource : IRenderSource
                         continue;
 
                     case "WindowMove":
-                        windowPositions[command.WindowId] = command.Position;
-                        isPositionDirty = true;
+                        if (windowCanvases.ContainsKey(command.WindowId))
+                        {
+                            windowPositions[command.WindowId] = command.Position;
+                            isPositionDirty = true;
+                        }
                         continue;
 
                     case "Window":
@@ -56,8 +59,7 @@ public sealed class CanvasRenderSource : IRenderSource
 
                 if (!windowCanvases.TryGetValue(command.WindowId, out Canvas? canvas))
                 {
-                    canvas = new Canvas(160, 120);
-                    windowCanvases[command.WindowId] = canvas;
+                    continue;
                 }
 
                 if (elementRenderers.TryGetValue(command.ElementType, out Action<Canvas, RenderCommand>? renderer))
@@ -145,6 +147,7 @@ public sealed class CanvasRenderSource : IRenderSource
         }
 
         windowPositions[id] = command.Position;
+        isPositionDirty = true;
         RenderWindow(windowCanvases[id], command);
     }
 
diff --git a/UI/GUI/Windows/Window.cs b/UI/GUI/Windows/Window.cs
index 2602278..d8508be 100644
--- a/UI/GUI/Windows/Window.cs
+++ b/UI/GUI/Windows/Window.cs
@@ -1,3 +1,4 @@
+using Cosmos.Kernel.System.Graphics;
 using RemSox.UI.GUI.Rendering;
 using RemSox.UI.GUI.UIEelements;
 
@@ -288,18 +289,21 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
     /// <summary>
     /// Updates the drag or resize interaction based on the current pointer position.
     /// </summary>
-    public void UpdateInteraction(Point pointerPosition)
+    public void UpdateInteraction(Point pointerPosition, Point screenSize)
     {
         if (currentInteraction == InteractionMode.Drag)
         {
             int newX = pointerPosition.X - dragOffset.X;
             int newY = pointerPosition.Y - dragOffset.Y;
 
-            // Cosmos DrawCanvas fails to render if coordinates are negative.
-            // Clamp to 0,0 to prevent the window from disappearing.
+            // Clamp left and top edges
             newX = Math.Max(0, newX);
             newY = Math.Max(0, newY);
 
+            // Clamp right and bottom edges
+            newX = Math.Min(screenSize.X - Size.Width, newX);
+            newY = Math.Min(screenSize.Y - Size.Height, newY);
+
             Position = new Point(newX, newY);
             Flush();
         }
@@ -319,24 +323,26 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
             if (currentInteraction is InteractionMode.ResizeRight or InteractionMode.ResizeBottomRight or InteractionMode.ResizeTopRight)
             {
                 newW = Math.Max(minWidth, interactionStartBounds.Width + dx);
+                newW = Math.Min(newW, screenSize.X - newX);
             }
             if (currentInteraction is InteractionMode.ResizeBottom or InteractionMode.ResizeBottomRight or InteractionMode.ResizeBottomLeft)
             {
                 newH = Math.Max(minHeight, interactionStartBounds.Height + dy);
+                newH = Math.Min(newH, screenSize.Y - newY);
             }
             if (currentInteraction is InteractionMode.ResizeLeft or InteractionMode.ResizeBottomLeft or InteractionMode.ResizeTopLeft)
             {
                 int maxDx = interactionStartBounds.Width - minWidth;
                 int clampedDx = Math.Min(dx, maxDx);
                 newX = Math.Max(0, interactionStartBounds.X + clampedDx);
-                newW = interactionStartBounds.Width - clampedDx;
+                newW = (interactionStartBounds.X + interactionStartBounds.Width) - newX;
             }
             if (currentInteraction is InteractionMode.ResizeTop or InteractionMode.ResizeTopLeft or InteractionMode.ResizeTopRight)
             {
                 int maxDy = interactionStartBounds.Height - minHeight;
                 int clampedDy = Math.Min(dy, maxDy);
                 newY = Math.Max(0, interactionStartBounds.Y + clampedDy);
-                newH = interactionStartBounds.Height - clampedDy;
+                newH = (interactionStartBounds.Y + interactionStartBounds.Height) - newY;
             }
 
             Position = new Point(newX, newY);
diff --git a/UI/GUI/Windows/WindowManager.cs b/UI/GUI/Windows/WindowManager.cs
index 782be91..2907ef0 100644
--- a/UI/GUI/Windows/WindowManager.cs
+++ b/UI/GUI/Windows/WindowManager.cs
@@ -37,13 +37,15 @@ public static class WindowManager
         Point pointerPosition = new(MouseManager.X, MouseManager.Y);
         bool leftButtonDown = MouseManager.LeftButton;
 
+        Canvas canvas = FullScreenCanvas.GetFullScreenCanvas();
+
         if (leftButtonDown && !wasLeftButtonDown)
         {
             activeInteractWindow = TryBeginInteract(pointerPosition);
         }
         else if (leftButtonDown && activeInteractWindow is not null)
         {
-            activeInteractWindow.UpdateInteraction(pointerPosition);
+            activeInteractWindow.UpdateInteraction(pointerPosition, new Point((int)canvas.Mode.Width, (int)canvas.Mode.Height));
         }
         else if (!leftButtonDown && activeInteractWindow is not null)
         {
@@ -58,7 +60,6 @@ public static class WindowManager
             focusedWindow?.HandleKeyEvent(keyEvent);
         }
 
-        Canvas canvas = FullScreenCanvas.GetFullScreenCanvas();
         CanvasRenderSource.CompositeAndDisplay(canvas, pointerPosition);
 
         lastPointerPosition = pointerPosition;
@@ -118,6 +119,15 @@ public static class WindowManager
             }
         }
 
+        if (focusedWindow == window)
+        {
+            focusedWindow = null;
+        }
+        if (activeInteractWindow == window)
+        {
+            activeInteractWindow = null;
+        }
+
         renderSource.Render([new RenderCommand { WindowId = window.Id, ElementId = window.Id, ElementType = "WindowClose", Position = window.Position, Properties = new Dictionary<string, object?>() }]);
     }
 
@@ -162,6 +172,15 @@ public static class WindowManager
 
         if (windowsToClose.Count > 0)
         {
+            if (focusedWindow != null && windowsToClose.Contains(focusedWindow))
+            {
+                focusedWindow = null;
+            }
+            if (activeInteractWindow != null && windowsToClose.Contains(activeInteractWindow))
+            {
+                activeInteractWindow = null;
+            }
+
             List<RenderCommand> closeCommands = [];
             foreach (Window window in windowsToClose)
             {