XFWM closing due to unhandled Xerror while using libreoffice

Hi,

I've experienced another xfwm crash while I was scrolling in a biggish document in libreoffice calc. This one was happening frequently while navigating said document.

I'm using xfwm 4.14.6 including patch from commit e2fbfac3 on FreeBSD.

Here is the error:

(xfwm4:3704): Gdk-ERROR **: 12:29:42.404: The program 'xfwm4' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial 2241129 error_code 143 request_code 138 (XFIXES) minor_code 22)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the GDK_SYNCHRONIZE environment
   variable to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
Qt WARNING: Unhandled client message:  "WM_S0"
Qt WARNING: Unhandled client message:  "_NET_WM_CM_S0"
Qt WARNING: Unhandled client message:  "COMPOSITING_MANAGER"
Qt WARNING: Unhandled client message:  "XFWM4_COMPOSITING_MANAGER"

If any further information or test is required I'll try to provide it.