diff --git a/CheckComboBox.md b/CheckComboBox.md
index 9f6912f..9348700 100644
--- a/CheckComboBox.md
+++ b/CheckComboBox.md
@@ -1,5 +1,5 @@
 # CheckComboBox
-Derives from Xceed.Wpf.Toolkit.Primitives.Selector
+Derives from Xceed.Wpf.Toolkit.Primitives.SelectAllSelector
 
 CheckComboBox is a combo box in which the items in the dropdown are preceded by a checkbox. As items are checked or unchecked, the Text property displayed above the dropdown is updated using the concatenated string representations of the checked items. The text displayed is formatted using the value of the Delimiter property to separate the individual strings.