Xfce crashes FreeBSD 11-CURRENT

[Ranjan1018 .]

Right-click on desktop - Desktop Settings… - click on the “Create a new
list, or load an existing one” - Type a non existent file name in the
windows with the title “Crete/Load Backdrop List” - Open

The laptop freezes and displays only a blank screen with the mouse cursor
and the text cursor on the top left corner. The only things I can do is to
press the power button for some seconds to switch off the laptop.

Note: I have some images in a Image list as background.
I am running vt(4) with KMS on Intel driver.
$ uname -a
FreeBSD ativ 11.0-CURRENT FreeBSD 11.0-CURRENT #0 r274845: Sat Nov 22
14:59:02 CET 2014     root at ativ:/usr/obj/usr/src/sys/NEWCONS  amd64

Maurizio