quit-interface in XP

Hello,

We have been porting our software from LWM 4.4 to LWW 4.4. When calling
the following method:

(defmethod window-close((self t))
   (capi:execute-with-interface self
    #'(lambda (intface force)
        (capi:quit-interface intface :force force)) self 
*force-quit-interface*))

we occasionally (most of the time this works OK though) get the following error
in XP (in Mac this error never occurs):

Condition: Throwing out (MP::PROCESS-TAG (:KILL)) when not in message-loop
Call to WIN32::WND-PROC (offset 510)
   WIN32:HWND     : #<Raw value #x000C01EA (786922)>
   WIN32::WMSG    : #<Raw value #x00000002 (2)>
   WIN32:WPARAM   : #<Raw value #x00000000 (0)>
   WIN32:LPARAM   : #<Raw value #x00000000 (0)>
   WIN32::DEFPROC : WIN32::DEF-WINDOW-PROC$RAW

Call to (SUBFUNCTION WIN32::|%FOREIGN-CALLABLE/wnd_proc_callback| 
(FLI:DEFINE-FOREIGN-CALLABLE "wnd_proc_callback")) (offset 68)
   FLI::%FOREIGN-CALL-STACK% : #<Raw value #x1EEAFBE4 (518716388)>

Call to %FUNCALL1-ON-LISP-STACK (offset 34)

Call to FLI::FOREIGN-CALLABLE-ENTRY-POINT-AUX-NESTED (offset 106)

Call to WIN32:DESTROY-WINDOW (offset 94)
   WIN32::H-WND : 655854

Binding frame:
   CLOS::*NEXT-METHODS* : NIL

Call to Anonymous compiled function #<function 203CFCC2> (offset 75)

Binding frame:
   CLOS::*NEXT-METHODS* : (#<function (METHOD CAPI:DESTROY 
(CAPI::BASIC-ELEMENT)) 20F12E42>)

Call to Anonymous compiled function #<function 203CF4F2> (offset 50)

Call to (METHOD CAPI:DESTROY (CAPI:SIMPLE-PANE)) (offset 75)
   CAPI::SELF : #<PWGL-FUNCTION-EDITOR-WINDOW "2D-Editor1" 21F88E04>

Binding frame:
   CLOS::*NEXT-METHODS* : (#<function (METHOD CAPI:DESTROY 
(CAPI:SIMPLE-PANE)) 20EFC352> #<function (METHOD CAPI:DESTROY 
(CAPI::BASIC-ELEMENT)) 20F12E42>)

Call to CLOS::NEXT-METHOD-CALL-1 (offset 68)
   CONS               : (METHOD CAPI:DESTROY (CAPI:INTERFACE))
   CLOS::NEXT-METHODS : (#<function (METHOD CAPI:DESTROY 
(CAPI:SIMPLE-PANE)) 20EFC352> #<function (METHOD CAPI:DESTROY 
(CAPI::BASIC-ELEMENT)) 20F12E42>)
   DBG::G0            : #<PWGL-FUNCTION-EDITOR-WINDOW "2D-Editor1" 21F88E04>

Catch frame: #<unbound>

Call to (METHOD CAPI:DESTROY (CAPI:INTERFACE)) (offset 63)
   CAPI::SELF : #<PWGL-FUNCTION-EDITOR-WINDOW "2D-Editor1" 21F88E04>

Binding frame:
   CLOS::*NEXT-METHODS* : NIL

Call to Anonymous compiled function #<function 203822F2> (offset 73)

Call to CAPI:QUIT-INTERFACE (offset 93)
   CAPI::PANE  : #<PWGL-FUNCTION-EDITOR-WINDOW "2D-Editor1" 21F88E04>
   CAPI::FORCE : T

Call to (SUBFUNCTION 1 (METHOD WINDOW-CLOSE (T))) (offset 31)
   INTFACE : #<PWGL-FUNCTION-EDITOR-WINDOW "2D-Editor1" 21F88E04>
   FORCE   : T


Mikael