Don't expose protected fields.

src/Avalonia.Controls.ColorPicker/ColorSlider/ColorSlider.cs

@@ -98,10 +98,10 @@ namespace Avalonia.Controls.Primitives
             int pixelWidth;
             int pixelHeight;
 
-            if (base._track != null)
+            if (base.Track != null)
             {
-                pixelWidth = Convert.ToInt32(base._track.Bounds.Width * scale);
+                pixelWidth = Convert.ToInt32(base.Track.Bounds.Width * scale);
-                pixelHeight = Convert.ToInt32(base._track.Bounds.Height * scale);
+                pixelHeight = Convert.ToInt32(base.Track.Bounds.Height * scale);
             }
             else
             {

src/Avalonia.Controls/Slider.cs

@@ -86,10 +86,10 @@ namespace Avalonia.Controls
             TickBar.TicksProperty.AddOwner<Slider>();
 
         // Slider required parts
-        protected bool _isDragging;
+        private bool _isDragging;
-        protected Track? _track;
+        private Track? _track;
-        protected Button? _decreaseButton;
+        private Button? _decreaseButton;
-        protected Button? _increaseButton;
+        private Button? _increaseButton;
         private IDisposable? _decreaseButtonPressDispose;
         private IDisposable? _decreaseButtonReleaseDispose;
         private IDisposable? _increaseButtonSubscription;
@@ -181,6 +181,26 @@ namespace Avalonia.Controls
             set { SetValue(TickPlacementProperty, value); }
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the <see cref="Slider"/> is currently being dragged.
+        /// </summary>
+        protected bool IsDragging => _isDragging;
+
+        /// <summary>
+        /// Gets the <see cref="Track"/> part of the <see cref="Slider"/>.
+        /// </summary>
+        protected Track? Track => _track;
+
+        /// <summary>
+        /// Gets the <see cref="Button"/> that decreases the <see cref="Slider"/> value.
+        /// </summary>
+        protected Button? DecreaseButton => _decreaseButton;
+
+        /// <summary>
+        /// Gets the <see cref="Button"/> that increases the <see cref="Slider"/> value.
+        /// </summary>
+        protected Button? IncreaseButton => _increaseButton;
+
         /// <inheritdoc/>
         protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
         {