Add comments + cleanup

osu.Game/Skinning/LegacySkin.cs

@@ -170,6 +170,7 @@ protected override Texture GetTextureForCharacter(char c)
             {
                 string textureName = $"{font}-{c}";
 
+                // Approximate value that brings character sizing roughly in-line with stable
                 float ratio = 36;
 
                 var texture = textures.Get($"{textureName}@2x");

osu.Game/Skinning/SkinnableDrawable.cs

@@ -18,6 +18,9 @@ public SkinnableDrawable(string name, Func<string, Drawable> defaultImplementati
     public class SkinnableDrawable<T> : SkinReloadableDrawable
         where T : Drawable
     {
+        /// <summary>
+        /// The displayed component. May or may not be a type-<typeparamref name="T"/> member.
+        /// </summary>
         protected Drawable Drawable { get; private set; }
 
         private readonly Func<string, T> createDefault;
@@ -45,7 +48,6 @@ public SkinnableDrawable(string name, Func<string, T> defaultImplementation, Fun
 
         protected override void SkinChanged(ISkinSource skin, bool allowFallback)
         {
-            Drawable = null;
             Drawable = skin.GetDrawableComponent(componentName);
 
             if (Drawable != null)