diff --git a/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs b/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
index 7d141fd890..1c27c00d1b 100644
--- a/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
+++ b/src/Markup/Perspex.Markup.Xaml/PerspexXamlLoader.cs
@@ -182,7 +182,7 @@ namespace Perspex.Markup.Xaml
             var asm = type.GetTypeInfo().Assembly.GetName().Name;
             var typeName = type.FullName;
             yield return new Uri("resm:" + typeName + ".xaml?assembly=" + asm);
-            yield return new Uri("resm:" + typeName + ".xaml?assembly=" + asm);
+            yield return new Uri("resm:" + typeName + ".paml?assembly=" + asm);
 
         }
     }
diff --git a/src/Perspex.Application/Designer/DesignerAssist.cs b/src/Perspex.Application/Designer/DesignerAssist.cs
index 49015d971f..de5518317f 100644
--- a/src/Perspex.Application/Designer/DesignerAssist.cs
+++ b/src/Perspex.Application/Designer/DesignerAssist.cs
@@ -78,6 +78,9 @@ namespace Perspex.DesignerSupport
                 {
                     window = new Window() {Content = original};
                 }
+
+                if (!window.IsSet(Window.SizeToContentProperty))
+                    window.SizeToContent = SizeToContent.WidthAndHeight;
             }
 
             s_currentWindow?.Close();