Remove ignored validate parameter.

src/Avalonia.Base/AvaloniaProperty.cs

@@ -302,8 +302,7 @@ namespace Avalonia
             string name,
             TValue defaultValue = default(TValue),
             bool inherits = false,
-            BindingMode defaultBindingMode = BindingMode.OneWay,
-            Func<THost, TValue, TValue> validate = null)
+            BindingMode defaultBindingMode = BindingMode.OneWay)
                 where THost : IAvaloniaObject
         {
             Contract.Requires<ArgumentNullException>(name != null);
@@ -335,8 +334,7 @@ namespace Avalonia
             Type ownerType,
             TValue defaultValue = default(TValue),
             bool inherits = false,
-            BindingMode defaultBindingMode = BindingMode.OneWay,
-            Func<THost, TValue, TValue> validate = null)
+            BindingMode defaultBindingMode = BindingMode.OneWay)
                 where THost : IAvaloniaObject
         {
             Contract.Requires<ArgumentNullException>(name != null);

src/Avalonia.Controls/DefinitionBase.cs

@@ -750,8 +750,8 @@ namespace Avalonia.Controls
         /// </remarks> 
         public static readonly AttachedProperty<string> SharedSizeGroupProperty =
             AvaloniaProperty.RegisterAttached<DefinitionBase, Control, string>(
-                "SharedSizeGroup",
-                validate: SharedSizeGroupPropertyValueValid);
+                "SharedSizeGroup"/*,
+                validate: SharedSizeGroupPropertyValueValid*/);
 
         /// <summary>
         /// Static ctor. Used for static registration of properties.

src/Avalonia.Controls/Grid.cs

@@ -2740,12 +2740,12 @@ namespace Avalonia.Controls
         public static readonly AttachedProperty<int> ColumnProperty =
             AvaloniaProperty.RegisterAttached<Grid, Control, int>(
                 "Column",
-                defaultValue: 0,
+                defaultValue: 0/*,
                 validate: (_, v) =>
                 {
                     if (v >= 0) return v;
                     else throw new ArgumentException("Invalid Grid.Column value.");
-                });
+                }*/);
 
         /// <summary>
         /// Row property. This is an attached property.
@@ -2761,12 +2761,12 @@ namespace Avalonia.Controls
         public static readonly AttachedProperty<int> RowProperty =
             AvaloniaProperty.RegisterAttached<Grid, Control, int>(
                 "Row",
-                defaultValue: 0,
+                defaultValue: 0/*,
                 validate: (_, v) =>
                 {
                     if (v >= 0) return v;
                     else throw new ArgumentException("Invalid Grid.Row value.");
-                });
+                }*/);
 
         /// <summary>
         /// ColumnSpan property. This is an attached property.
@@ -2781,12 +2781,12 @@ namespace Avalonia.Controls
         public static readonly AttachedProperty<int> ColumnSpanProperty =
             AvaloniaProperty.RegisterAttached<Grid, Control, int>(
                 "ColumnSpan",
-                defaultValue: 1,
+                defaultValue: 1/*,
                 validate: (_, v) =>
                 {
                     if (v >= 1) return v;
                     else throw new ArgumentException("Invalid Grid.ColumnSpan value.");
-                });
+                }*/);
 
         /// <summary>
         /// RowSpan property. This is an attached property.
@@ -2801,12 +2801,12 @@ namespace Avalonia.Controls
         public static readonly AttachedProperty<int> RowSpanProperty =
             AvaloniaProperty.RegisterAttached<Grid, Control, int>(
                 "RowSpan",
-                defaultValue: 1,
+                defaultValue: 1/*,
                 validate: (_, v) =>
                 {
                     if (v >= 1) return v;
                     else throw new ArgumentException("Invalid Grid.RowSpan value.");
-                });
+                }*/);
 
         /// <summary>
         /// IsSharedSizeScope property marks scoping element for shared size.

src/Avalonia.Controls/NativeMenu.Export.cs

@@ -52,13 +52,13 @@ namespace Avalonia.Controls
         }
 
         public static readonly AttachedProperty<NativeMenu> MenuProperty
-            = AvaloniaProperty.RegisterAttached<NativeMenu, AvaloniaObject, NativeMenu>("Menu", validate:
+            = AvaloniaProperty.RegisterAttached<NativeMenu, AvaloniaObject, NativeMenu>("Menu"/*, validate:
                 (o, v) =>
                 {
                     if(!(o is Application || o is TopLevel))
                         throw new InvalidOperationException("NativeMenu.Menu property isn't valid on "+o.GetType());
                     return v;
-                });
+                }*/);
 
         public static void SetMenu(AvaloniaObject o, NativeMenu menu) => o.SetValue(MenuProperty, menu);
         public static NativeMenu GetMenu(AvaloniaObject o) => o.GetValue(MenuProperty);

src/Avalonia.Controls/Notifications/NotificationCard.cs

@@ -118,7 +118,7 @@ namespace Avalonia.Controls.Notifications
         /// Defines the CloseOnClick property.
         /// </summary>
         public static readonly AvaloniaProperty CloseOnClickProperty =
-          AvaloniaProperty.RegisterAttached<Button, bool>("CloseOnClick", typeof(NotificationCard), validate: CloseOnClickChanged);
+          AvaloniaProperty.RegisterAttached<Button, bool>("CloseOnClick", typeof(NotificationCard)/*, validate: CloseOnClickChanged*/);
 
         private static bool CloseOnClickChanged(Button button, bool value)
         {

tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Attached.cs

@@ -38,18 +38,7 @@ namespace Avalonia.Base.UnitTests
             public static readonly AttachedProperty<string> FooProperty =
                 AvaloniaProperty.RegisterAttached<Class1, Base, string>(
                     "Foo",
-                    "foodefault",
-                    validate: ValidateFoo);
-
-            private static string ValidateFoo(AvaloniaObject arg1, string arg2)
-            {
-                if (arg2 == "throw")
-                {
-                    throw new IndexOutOfRangeException();
-                }
-
-                return arg2;
-            }
+                    "foodefault");
         }
 
         private class Class2 : Base