diff --git a/Bin/net40/SunnyUI.Demo.exe b/Bin/net40/SunnyUI.Demo.exe
index 5d805b1f..efb7031a 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 df59d742..380154a1 100644
Binary files a/Bin/net40/SunnyUI.dll and b/Bin/net40/SunnyUI.dll differ
diff --git a/SunnyUI/Controls/UIControl.cs b/SunnyUI/Controls/UIControl.cs
index 3cbf9367..882de524 100644
--- a/SunnyUI/Controls/UIControl.cs
+++ b/SunnyUI/Controls/UIControl.cs
@@ -176,6 +176,7 @@ namespace Sunny.UI
                 if (radius != value)
                 {
                     radius = Math.Max(0, value);
+                    radius = Math.Min(radius, Math.Min(Width, Height));
                     Invalidate();
                 }
             }
diff --git a/SunnyUI/Controls/UIPanel.cs b/SunnyUI/Controls/UIPanel.cs
index 2f84ec0d..18217bad 100644
--- a/SunnyUI/Controls/UIPanel.cs
+++ b/SunnyUI/Controls/UIPanel.cs
@@ -204,6 +204,7 @@ namespace Sunny.UI
                 if (radius != value)
                 {
                     radius = Math.Max(0, value);
+                    radius = Math.Min(radius, Math.Min(Width, Height));
                     OnRadiusChanged(radius);
                     Invalidate();
                 }