diff --git a/Bin/net40/SunnyUI.dll b/Bin/net40/SunnyUI.dll
index 1d9442d3..6af16ce6 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 7e1499ae..0498cd6c 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 11ad7236..1793e4c7 100644
Binary files a/Bin/net5.0-windows/SunnyUI.dll and b/Bin/net5.0-windows/SunnyUI.dll differ
diff --git a/Bin/netcoreapp3.1/SunnyUI.dll b/Bin/netcoreapp3.1/SunnyUI.dll
index 75caa640..3e466917 100644
Binary files a/Bin/netcoreapp3.1/SunnyUI.dll and b/Bin/netcoreapp3.1/SunnyUI.dll differ
diff --git a/SunnyUI/Controls/UIComboBox.cs b/SunnyUI/Controls/UIComboBox.cs
index 5faac9f4..9bb9f2d4 100644
--- a/SunnyUI/Controls/UIComboBox.cs
+++ b/SunnyUI/Controls/UIComboBox.cs
@@ -42,11 +42,21 @@ namespace Sunny.UI
             ListBox.DisplayMemberChanged += Box_DisplayMemberChanged;
             ListBox.ValueMemberChanged += Box_ValueMemberChanged;
             ListBox.SelectedValueChanged += ListBox_SelectedValueChanged;
+            ListBox.ItemsCountChange += ListBox_ItemsCountChange;
             edit.TextChanged += Edit_TextChanged;
             DropDownWidth = 150;
             fullControlSelect = true;
         }
 
+        private void ListBox_ItemsCountChange(object sender, EventArgs e)
+        {
+            if (ListBox.Count == 0)
+            {
+                Text = "";
+                edit.Text = "";
+            }
+        }
+
         public new EventHandler TextChanged;
 
         private void Edit_TextChanged(object sender, EventArgs e)
@@ -142,7 +152,8 @@ namespace Sunny.UI
 
         private void UIComboBox_ButtonClick(object sender, EventArgs e)
         {
-            ItemForm.Show(this, new Size(DropDownWidth < Width ? Width : DropDownWidth, CalcItemFormHeight()));
+            if (Items.Count > 0)
+                ItemForm.Show(this, new Size(DropDownWidth < Width ? Width : DropDownWidth, CalcItemFormHeight()));
         }
 
         public override void SetStyleColor(UIBaseStyle uiColor)