Description of problem:
Crashed (again) when removing all entries from the background image list before all thumbs were created. Possibly related to bug 1120688 and bug 1172999.

Version-Release number of selected component:
xfdesktop-4.10.3-3.fc20

Additional info:
reporter:       libreport-2.2.3
backtrace_rating: 4
cmdline:        /usr/bin/xfdesktop-settings
crash_function: is_end
executable:     /usr/bin/xfdesktop-settings
kernel:         3.19.5-100.fc20.x86_64
runlevel:       N 5
type:           CCpp
uid:            1000
var_log_messages: [System Logs]:\n-- Logs begin at Thu 2014-03-13 15:13:02 CET, end at Mon 2015-05-04 08:51:07 CEST. --

Truncated backtrace:
Thread no. 1 (6 frames)
 #0 is_end at gsequence.c:200
 #1 gtk_list_store_set_valist at gtkliststore.c:897
 #2 gtk_list_store_set at gtkliststore.c:941
 #3 xfdesktop_settings_do_single_preview at main.c:189
 #4 xfdesktop_settings_create_all_previews at main.c:235
 #5 g_thread_proxy at gthread.c:798