diff --git a/Perspex.Diagnostics/DevTools.cs b/Perspex.Diagnostics/DevTools.cs
index da0c4bd3be..8f80c8a30d 100644
--- a/Perspex.Diagnostics/DevTools.cs
+++ b/Perspex.Diagnostics/DevTools.cs
@@ -118,10 +118,8 @@ namespace Perspex.Diagnostics
             {
                 Window window = new Window
                 {
-                    // HACK: Set width and height here as a quick fix as there's a problem with 
-                    // the dev tools window hanging when it's set to auto-size.
-                    Width = 800,
-                    Height = 600,
+                    Width = 1024,
+                    Height = 512,
                     Content = new DevTools
                     {
                         Root = (Window)sender,
diff --git a/Perspex.Layout/LayoutManager.cs b/Perspex.Layout/LayoutManager.cs
index 864370d2c1..f08ca7bf50 100644
--- a/Perspex.Layout/LayoutManager.cs
+++ b/Perspex.Layout/LayoutManager.cs
@@ -206,9 +206,9 @@ namespace Perspex.Layout
 
                 this.toArrange = new Heap<Item>(HeapType.Minimum);
 
-                if (!this.Root.IsArrangeValid)
+                if (!this.Root.IsArrangeValid && this.Root.IsMeasureValid)
                 {
-                    this.Root.Arrange(new Rect(this.Root.ClientSize));
+                    this.Root.Arrange(new Rect(this.Root.DesiredSize.Value));
                 }
 
                 if (this.toMeasure.Count > 0)