Remove ScrollBar pseudoclasses.

Perspex.Controls/Primitives/ScrollBar.cs

@@ -34,15 +34,6 @@ namespace Perspex.Controls.Primitives
         public static readonly PerspexProperty<Orientation> OrientationProperty =
             PerspexProperty.Register<ScrollBar, Orientation>(nameof(Orientation));
 
-        /// <summary>
-        /// Initializes static members of the <see cref="ScrollBar"/> class.
-        /// </summary>
-        static ScrollBar()
-        {
-            Control.PseudoClass(OrientationProperty, x => x == Orientation.Horizontal, ":horizontal");
-            Control.PseudoClass(OrientationProperty, x => x == Orientation.Vertical, ":vertical");
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="ScrollBar"/> class.
         /// </summary>

Perspex.Themes.Default/ScrollBarStyle.cs

@@ -26,7 +26,7 @@ namespace Perspex.Themes.Default
                         new Setter(ScrollBar.TemplateProperty, ControlTemplate.Create<ScrollBar>(this.Template)),
                     },
                 },
-                new Style(x => x.OfType<ScrollBar>().Class(":horizontal"))
+                new Style(x => x.OfType<ScrollBar>().PropertyEquals(ScrollBar.OrientationProperty, Orientation.Horizontal))
                 {
                     Setters = new[]
                     {
@@ -34,14 +34,14 @@ namespace Perspex.Themes.Default
                         new Setter(ScrollBar.HeightProperty, 10.0),
                     },
                 },
-                new Style(x => x.OfType<ScrollBar>().Class(":horizontal").Template().Name("thumb"))
+                new Style(x => x.OfType<ScrollBar>().PropertyEquals(ScrollBar.OrientationProperty, Orientation.Horizontal).Template().Name("thumb"))
                 {
                     Setters = new[]
                     {
                         new Setter(Thumb.MinWidthProperty, 10.0),
                     },
                 },
-                new Style(x => x.OfType<ScrollBar>().Class(":vertical"))
+                new Style(x => x.OfType<ScrollBar>().PropertyEquals(ScrollBar.OrientationProperty, Orientation.Vertical))
                 {
                     Setters = new[]
                     {
@@ -49,7 +49,7 @@ namespace Perspex.Themes.Default
                         new Setter(ScrollBar.WidthProperty, 10.0),
                     },
                 },
-                new Style(x => x.OfType<ScrollBar>().Class(":vertical").Template().Name("thumb"))
+                new Style(x => x.OfType<ScrollBar>().PropertyEquals(ScrollBar.OrientationProperty, Orientation.Vertical).Template().Name("thumb"))
                 {
                     Setters = new[]
                     {