diff --git a/Bin/net40/SunnyUI.Demo.exe b/Bin/net40/SunnyUI.Demo.exe
index 764100ee..4a4e25cb 100644
Binary files a/Bin/net40/SunnyUI.Demo.exe and b/Bin/net40/SunnyUI.Demo.exe differ
diff --git a/Bin/net40/SunnyUI.dll b/Bin/net40/SunnyUI.dll
index 7cc9d3e9..eb6e12cb 100644
Binary files a/Bin/net40/SunnyUI.dll and b/Bin/net40/SunnyUI.dll differ
diff --git a/Bin/net45/SunnyUI.dll b/Bin/net45/SunnyUI.dll
index 8bf38f42..6d6ba674 100644
Binary files a/Bin/net45/SunnyUI.dll and b/Bin/net45/SunnyUI.dll differ
diff --git a/Bin/net5.0-windows/SunnyUI.dll b/Bin/net5.0-windows/SunnyUI.dll
index 633f9eba..8abbfd11 100644
Binary files a/Bin/net5.0-windows/SunnyUI.dll and b/Bin/net5.0-windows/SunnyUI.dll differ
diff --git a/Bin/net5.0-windows/ref/SunnyUI.dll b/Bin/net5.0-windows/ref/SunnyUI.dll
index eb1c2c8d..bed9e61d 100644
Binary files a/Bin/net5.0-windows/ref/SunnyUI.dll and b/Bin/net5.0-windows/ref/SunnyUI.dll differ
diff --git a/Bin/netcoreapp3.1/SunnyUI.dll b/Bin/netcoreapp3.1/SunnyUI.dll
index 09c3b6ba..4042eae6 100644
Binary files a/Bin/netcoreapp3.1/SunnyUI.dll and b/Bin/netcoreapp3.1/SunnyUI.dll differ
diff --git a/SunnyUI.Demo/Controls/FFlowLayoutPanel.cs b/SunnyUI.Demo/Controls/FFlowLayoutPanel.cs
index e5122212..587b4966 100644
--- a/SunnyUI.Demo/Controls/FFlowLayoutPanel.cs
+++ b/SunnyUI.Demo/Controls/FFlowLayoutPanel.cs
@@ -28,10 +28,10 @@
                 Text = "Button" + index++.ToString("D2")
             };
 
-            //可以用原生方法Controls.Add
-            uiFlowLayoutPanel1.Controls.Add(btn);
-            //或者封装的方法Add
-            //uiFlowLayoutPanel1.Add(btn);
+            //建议用封装的方法Add
+            uiFlowLayoutPanel1.Add(btn);
+            //也可以用原生方法Controls.Add（不推荐）
+            //uiFlowLayoutPanel1.Controls.Add(btn);    
 
             uiButton3.Enabled = true;
         }
diff --git a/SunnyUI/Controls/UIFlowLayoutPanel.cs b/SunnyUI/Controls/UIFlowLayoutPanel.cs
index 57658f71..2e60093f 100644
--- a/SunnyUI/Controls/UIFlowLayoutPanel.cs
+++ b/SunnyUI/Controls/UIFlowLayoutPanel.cs
@@ -24,7 +24,6 @@ using System.ComponentModel;
 using System.Drawing;
 using System.Drawing.Drawing2D;
 using System.Windows.Forms;
-using System.Windows.Forms.Layout;
 
 namespace Sunny.UI
 {
@@ -65,11 +64,6 @@ namespace Sunny.UI
             timer.Stop();
         }
 
-        public override LayoutEngine LayoutEngine
-        {
-            get { return Panel.LayoutEngine; }
-        }
-
         [DefaultValue(System.Windows.Forms.FlowDirection.LeftToRight)]
         [Localizable(true)]
         public FlowDirection FlowDirection
diff --git a/SunnyUI/Controls/UIImageListBox.cs b/SunnyUI/Controls/UIImageListBox.cs
index c5ca8b46..94260eaf 100644
--- a/SunnyUI/Controls/UIImageListBox.cs
+++ b/SunnyUI/Controls/UIImageListBox.cs
@@ -362,20 +362,20 @@ namespace Sunny.UI
                 }
             }
 
-            protected override void WndProc(ref Message m)
-            {
-                if (IsDisposed || Disposing) return;
-                if (IsHandleCreated)
-                {
-                    if (m.Msg == Win32.User.WM_ERASEBKGND)
-                    {
-                        m.Result = IntPtr.Zero;
-                        return;
-                    }
-                }
-
-                base.WndProc(ref m);
-            }
+            //protected override void WndProc(ref Message m)
+            //{
+            //    if (IsDisposed || Disposing) return;
+            //    if (IsHandleCreated)
+            //    {
+            //        if (m.Msg == Win32.User.WM_ERASEBKGND)
+            //        {
+            //            m.Result = IntPtr.Zero;
+            //            return;
+            //        }
+            //    }
+            //
+            //    base.WndProc(ref m);
+            //}
 
             public ImageListBox()
             {
diff --git a/SunnyUI/Controls/UIListBox.cs b/SunnyUI/Controls/UIListBox.cs
index f1b7e7fb..f32f4d61 100644
--- a/SunnyUI/Controls/UIListBox.cs
+++ b/SunnyUI/Controls/UIListBox.cs
@@ -607,11 +607,11 @@ namespace Sunny.UI
                     ItemsInsert?.Invoke(this, EventArgs.Empty);
                 }
 
-                if (m.Msg == Win32.User.WM_ERASEBKGND)
-                {
-                    m.Result = IntPtr.Zero;
-                    return;
-                }
+                //if (m.Msg == Win32.User.WM_ERASEBKGND)
+                //{
+                //    m.Result = IntPtr.Zero;
+                //    return;
+                //}
             }
 
             base.WndProc(ref m);
diff --git a/SunnyUI/Controls/UITransfer.cs b/SunnyUI/Controls/UITransfer.cs
index ce167e46..c3f8ec13 100644
--- a/SunnyUI/Controls/UITransfer.cs
+++ b/SunnyUI/Controls/UITransfer.cs
@@ -46,6 +46,14 @@ namespace Sunny.UI
             l2.ItemsCountChange += L2_ItemsCountChange;
         }
 
+        [DefaultValue(true)]
+        [Description("显示多选按钮"), Category("SunnyUI")]
+        public bool ShowMulti
+        {
+            get => b1.Visible;
+            set => b1.Visible = b4.Visible = value;
+        }
+
         private void L2_ItemsCountChange(object sender, EventArgs e)
         {
             ItemsRightCountChange?.Invoke(this, e);
@@ -84,12 +92,17 @@ namespace Sunny.UI
         [Browsable(false)]
         public ListBox ListBoxRight => l2.ListBox;
 
+        public delegate void ItemChange(object sender, object item);
+
+        public event ItemChange ItemAdd;
+        public event ItemChange ItemRemove;
 
         private void b1_Click(object sender, EventArgs e)
         {
             foreach (object item in l1.Items)
             {
                 l2.Items.Add(item);
+                ItemAdd?.Invoke(this, item);
             }
 
             l1.Items.Clear();
@@ -106,6 +119,7 @@ namespace Sunny.UI
                 int idx = l1.SelectedIndex;
                 object item = l1.SelectedItem;
                 l2.Items.Add(item);
+                ItemAdd?.Invoke(this, item);
                 l1.Items.Remove(item);
 
                 if (l2.Items.Count > 0)
@@ -132,6 +146,7 @@ namespace Sunny.UI
                 int idx = l2.SelectedIndex;
                 object item = l2.SelectedItem;
                 l1.Items.Add(item);
+                ItemRemove?.Invoke(this, item);
                 l2.Items.Remove(item);
 
                 if (l1.Items.Count > 0)
@@ -156,6 +171,7 @@ namespace Sunny.UI
             foreach (object item in l2.Items)
             {
                 l1.Items.Add(item);
+                ItemRemove?.Invoke(this, item);
             }
 
             l2.Items.Clear();