_CBtreeKeyDown
Define a callback to a key pressed event.
Prototype :
fun [ObjTree fun [ ObjTree u0 I I] u1 u0] ObjTree
- ObjTree : any button object
- fun [ ObjTree u0 I I] u1 : a callback
- u0 : an user parameter, at your convenience
Return : ObjTree the same object or nil if error
See also :
Example :