void SetClickback (long start, long end, wxClickbackFunc f, void *data,
wxStyleDelta *hiliteDelta = NULL, Bool callOnDown = FALSE)
Installs a clickback for the given region of text. See also
Clickbacks (section 
).
The format of the clickback function f is:
typedef void (*wxClickbackFunc) (wxMediaEdit *edit, long start, long end, void *data)
The value of data is passed on to the clickback function when it is invoked.
hiliteDelta is applied to the clickback text when the user has clicked and is still holding the mouse over the clickback. If hiliteDelta is NULL, then the clickback region's style is not changed when it is being selected.
If callOnDown is TRUE, the clickback is called immediately when the user clicks the mouse button down, instead of after a mouse-up event. The hiliteData argument is not used in this case.