How to force the CheckedListBoxControl to change the item's state only when user clicks in the Glyph area.

To accomplish this task, you need to implement the boolean property (allowChangeCheck) in the CheckedListBoxControl descendant, which defines whether changing the check state is allowed. You need to create your own ListBoxControlState descendant for the appropriate state based on the SelectionMode that you want to assign for the CheckedListBoxControl, and override its MouseUp method to change the value of the allowChangeCheck property.

SelectionMode.One - SingleSelectState,
SelectionMode.MultiSimple - MultiSimpleSelectState,
SelectionMode.MultiExtended - ExtendedMultiSelectState,
SelectionMode.None - UnselectableState

Then, override the OnchangeCheck method of the Checked ListBoxControl class and suppress further processing, if the allowCHangeCheck property is false.