treecombobox FocusOnClick property
Previous  Top  Next
Applies to
tcTreeComboBox component as subproperty of AttachedLabel structure.  

property FocusOnClick: Boolean; // True by default  

The FocusOnClick property controls whether the control, associated with the attached label, should accept focus when user clicks the label with mouse.  
Set FocusOnClick to True if you want to switch focus to the control when user clicks the label, or set it to False otherwise.  

Additionally you can use OnLabelClick and OnLabelDblClick events of the control.