bug(?) in text-editor-pane / Goatee

Hi all,

I've given up looking for this one for now, maybe people familiar with 
the code in question know what's going on. If you simply set the 
gadget-value of a text-editor-pane to a string with a newline in it (I 
assume that's how you set up multiline text, right?) and then set a new 
value, moving the cursor (home key in this example) can yield the 
following error:

> (setf (gadget-value *edit*) (format nil "test~%test"))

> (setf (gadget-value *edit*) "test")

The value -1 is not of type (MOD 536870911).
   [Condition of type TYPE-ERROR]

Restarts:
  0: [ABORT] Return to application command loop
  1: [TERMINATE-THREAD] Terminate this thread (#<THREAD {A8629D9}>)

Backtrace:
  0: ((SB-PCL::FAST-METHOD GOATEE::BUFFER-STRING 
(GOATEE::BASIC-BUFFER)) #<unavailable argument> #<unavailable argument> 
#<GOATEE::EDITABLE-BUFFER {AA30B61}> NIL)
  1: ((SB-PCL::FAST-METHOD HANDLE-EVENT (TEXT-FIELD-PANE 
KEY-PRESS-EVENT)) (#(NIL 65) . #()) #<unavailable argument> 
#<TEXT-EDITOR-PANE FORM-EDIT {A8BB141}> #<KEY-PRESS-EVENT {B491439}>)
  2: (CLIM-INTERNALS::HANDLE-NON-STREAM-EVENT 
#<CLIM-INTERNALS::PORT-EVENT-QUEUE {A862931}>)
  3: ((SB-PCL::FAST-METHOD STREAM-INPUT-WAIT
[ ... ]

The value doesn't have to be -1 btw...

If I'm not mistaken, the problem is that additional undefined characters 
are inserted mistakenly (visible cues too). The size of the 
editable-buffer is not correspondingly updated, so after deletion 
there's a negative size value.

Thanks in advance for any help,

Chris