diff --git a/CheckComboBox.md b/CheckComboBox.md
index 5b0826c..118809c 100644
--- a/CheckComboBox.md
+++ b/CheckComboBox.md
@@ -22,6 +22,7 @@ CheckComboBox is a combo box in which the items in the dropdown are preceded by
 | Delimiter | Gets or sets the string used to separate the concatenated string representations of the checked items. (Inherited from Selector) |
 | IsDropDownOpen | Gets or sets a value indicating whether the combo box drop-down is currently open. |
 | IsEditable | Gets or sets a value that enables or disables editing of the text in the Textbox of the CheckComboBox. Values entered must be separated by the **Delimiter**. Values entered that are not in the list or that are duplicates will be removed. Selection will be active on LostFocus. Default is False. |
+| IsSelectAllActive | Gets or sets if the "Select All" option is visible as a SelectorItem. True if the "Select All" option is vislble; false otherwise. By default, false. |
 | MaxDropDownHeight | Gets or sets the maximum height of the popup. |
 | SelectedItem | Gets or sets the last checked item. (Inherited from Selector) |
 | SelectedItems | Gets the collection of checked items. (Inherited from Selector) |