To enable this feature, set the ASPxListBox's EnableSelectAll option to true. When the CheckColumn selection mode is enabled for the list box, end-users can select all items using the "Select All" check box at the top of the list box. SelectItems, UnselectItems client methods). The control does not function as expected, though. I can add it manually then use the ExistingBindings tab to point the binding to the new control. I am still not able to select the ComboBoċdit control because it is not in the list. Also, to apply an item selection on the client side, use a specific client API (the editor's GetSelectedItems, As far as the CBM.I selected DevExpress v.7.2.1 however, I have 7.2.3 installed. Use the SelectedItems or SelectedIndices properties to obtain a collection of selected items. When Multiple Selection is enabled, use the item's Selected property to specify individual items' selection state. CheckColumn - End-users can select multiple items within the editor by clicking list items.Multiple - End-users can select multiple items within the editor by clicking list items while pressing Ctrl (to add an individual item) or Shift (to select a range of items).Single - End-users can select only one item within the editor.Depending on this property's setting, the following selection modes are available within the ASPxListBox editor: The editor's SelectionMode property controls selection behavior. The DevExpress ASP.NET List Box ( ASPxListBox) editor allows you to select multiple list items at the same time.