Don't allow placement of IConfigurableDrawables

osu.Game/Overlays/SkinEditor/SkinComponentToolbox.cs

@@ -61,6 +61,7 @@ private void reloadComponents()
             fill.Clear();
 
             var skinnableTypes = SerialisedDrawableInfo.GetAllAvailableDrawables(ruleset);
+
             foreach (var type in skinnableTypes)
                 attemptAddComponent(type);
         }
@@ -82,6 +83,10 @@ private void attemptAddComponent(Type type)
                     Expanding = contractOtherButtons,
                 });
             }
+            catch (MissingMethodException)
+            {
+                // Some components may not have a primary constructure (ie. IConfigurableDrawables that aren't supposed to be placed by a user).
+            }
             catch (DependencyNotRegisteredException)
             {
                 // This loading code relies on try-catching any dependency injection errors to know which components are valid for the current target screen.

osu.Game/Skinning/IConfigurableDrawable.cs

@@ -10,5 +10,7 @@ public interface IConfigurableDrawable : ISerialisableDrawable
         /// Will be called to restore a sane and known state.
         /// </summary>
         void ApplyDefaults();
+
+        bool ISerialisableDrawable.IsPlaceable => false;
     }
 }