modified some styles

src/Shared/HandyControl_Shared/Controls/Attach/BorderElement.cs

@@ -34,8 +34,8 @@ namespace HandyControl.Controls
                 }
                 else
                 {
-                    BindingOperations.ClearBinding(border, FrameworkElement.MinWidthProperty);
-                    BindingOperations.ClearBinding(border, FrameworkElement.MinHeightProperty);
+                    BindingOperations.ClearBinding(border, FrameworkElement.ActualWidthProperty);
+                    BindingOperations.ClearBinding(border, FrameworkElement.ActualHeightProperty);
                     BindingOperations.ClearBinding(border, Border.CornerRadiusProperty);
                 }
             }

src/Shared/HandyControl_Shared/Controls/Attach/RectangleAttach.cs

@@ -0,0 +1,45 @@
+using System.Windows;
+using System.Windows.Data;
+using System.Windows.Shapes;
+using HandyControl.Data;
+using HandyControl.Tools.Converter;
+
+namespace HandyControl.Controls
+{
+    public class RectangleAttach
+    {
+        public static readonly DependencyProperty CircularProperty = DependencyProperty.RegisterAttached(
+            "Circular", typeof(bool), typeof(RectangleAttach), new PropertyMetadata(ValueBoxes.FalseBox, OnCircularChanged));
+
+        private static void OnCircularChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            if (d is Rectangle rectangle)
+            {
+                if ((bool)e.NewValue)
+                {
+                    var binding = new MultiBinding
+                    {
+                        Converter = new RectangleCircularConverter()
+                    };
+                    binding.Bindings.Add(new Binding(FrameworkElement.ActualWidthProperty.Name) { Source = rectangle });
+                    binding.Bindings.Add(new Binding(FrameworkElement.ActualHeightProperty.Name) { Source = rectangle });
+                    rectangle.SetBinding(Rectangle.RadiusXProperty, binding);
+                    rectangle.SetBinding(Rectangle.RadiusYProperty, binding);
+                }
+                else
+                {
+                    BindingOperations.ClearBinding(rectangle, FrameworkElement.ActualWidthProperty);
+                    BindingOperations.ClearBinding(rectangle, FrameworkElement.ActualHeightProperty);
+                    BindingOperations.ClearBinding(rectangle, Rectangle.RadiusXProperty);
+                    BindingOperations.ClearBinding(rectangle, Rectangle.RadiusYProperty);
+                }
+            }
+        }
+
+        public static void SetCircular(DependencyObject element, bool value)
+            => element.SetValue(CircularProperty, value);
+
+        public static bool GetCircular(DependencyObject element)
+            => (bool) element.GetValue(CircularProperty);
+    }
+}