diff --git a/Bin/SunnyUI.dll b/Bin/SunnyUI.dll
index 76cc7b01..965b70fd 100644
Binary files a/Bin/SunnyUI.dll and b/Bin/SunnyUI.dll differ
diff --git a/Bin/SunnyUI.pdb b/Bin/SunnyUI.pdb
index 40c4c943..c21a7265 100644
Binary files a/Bin/SunnyUI.pdb and b/Bin/SunnyUI.pdb differ
diff --git a/SunnyUI.Demo/Bin/SunnyUI.dll b/SunnyUI.Demo/Bin/SunnyUI.dll
index 76cc7b01..965b70fd 100644
Binary files a/SunnyUI.Demo/Bin/SunnyUI.dll and b/SunnyUI.Demo/Bin/SunnyUI.dll differ
diff --git a/SunnyUI/Controls/UICheckBoxGroup.cs b/SunnyUI/Controls/UICheckBoxGroup.cs
index e7615f65..48029e4d 100644
--- a/SunnyUI/Controls/UICheckBoxGroup.cs
+++ b/SunnyUI/Controls/UICheckBoxGroup.cs
@@ -110,6 +110,7 @@ namespace Sunny.UI
                 {
                     UICheckBox box = new UICheckBox
                     {
+                        BackColor = Color.Transparent,
                         Font = Font,
                         Parent = this,
                         Tag = i,
@@ -132,6 +133,7 @@ namespace Sunny.UI
 
                 boxes[i].Left = startX + ItemSize.Width * columnIndex + ColumnInterval * columnIndex;
                 boxes[i].Top = startY + ItemSize.Height * rowIndex + RowInterval * rowIndex;
+                boxes[i].Size = ItemSize;
                 boxes[i].Show();
             }
         }
diff --git a/SunnyUI/Controls/UIRadioButtonGroup.cs b/SunnyUI/Controls/UIRadioButtonGroup.cs
index 131db953..8a4fd83b 100644
--- a/SunnyUI/Controls/UIRadioButtonGroup.cs
+++ b/SunnyUI/Controls/UIRadioButtonGroup.cs
@@ -94,6 +94,7 @@ namespace Sunny.UI
                 {
                     UIRadioButton button = new UIRadioButton
                     {
+                        BackColor = Color.Transparent,
                         Font = Font,
                         Parent = this,
                         Tag = i,
@@ -116,6 +117,7 @@ namespace Sunny.UI
 
                 buttons[i].Left = startX + ItemSize.Width * columnIndex + ColumnInterval * columnIndex;
                 buttons[i].Top = startY + ItemSize.Height * rowIndex + RowInterval * rowIndex;
+                buttons[i].Size = ItemSize;
                 buttons[i].Show();
             }
         }