Trying to fix intermittent test failure.

src/Markup/Perspex.Markup.Xaml/Context/PerspexNamespaceRegistry.cs

@@ -58,11 +58,11 @@ namespace Perspex.Markup.Xaml.Context
 
             if (!IsClrNamespace(name))
             {
+                ScanNewAssemblies();
                 result = _namespaces.FirstOrDefault(x => x.Name == name);
 
                 if (result == null)
                 {
-                    ScanNewAssemblies();
                     result = _namespaces.FirstOrDefault(x => x.Name == name);
                 }
             }

tests/Perspex.Markup.Xaml.UnitTests/StyleTests.cs

@@ -92,9 +92,6 @@ namespace Perspex.Markup.Xaml.UnitTests
         [Fact]
         public void StyleResource_Can_Be_Assigned_To_Setter()
         {
-            // For some reason this type can't always be found if we don't do this.
-            var hack = typeof(KeyboardNavigation);
-
             using (UnitTestApplication.Start(TestServices.StyledWindow))
             {
                 var xaml = @"