[Maxima] debugger-hook?

[pol]

I  have just got the error 

  Maxima encountered a Lisp error: Type-error in   
 KERNEL::OBJECT-NOT-LIST-ERROR-HANDLER:    |&STYLE,[POINTS,4,3,3]| is not of
type LIST
  Automatically continuing.
  To reenable the Lisp debugger set *debugger-hook* to nil.

I cannot find any commaand in wxmaxima to do that
I have tried 
   debugger-hook:nil
but no avail


Any hints?

thank you 
Pol