Description of problem:
checking for updates and moving between the tabs in the meantime (software browsing, installed software and updates)

Version-Release number of selected component:
gnome-software-3.13.91-1.fc21

Additional info:
reporter:       libreport-2.2.3
backtrace_rating: 4
cmdline:        /usr/bin/gnome-software --gapplication-service
crash_function: g_type_check_instance_cast
executable:     /usr/bin/gnome-software
kernel:         3.16.2-301.fc21.x86_64
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (9 frames)
 #0 g_type_check_instance_cast at gtype.c:4013
 #1 app_state_changed at gs-feature-tile.c:58
 #7 g_object_notify_queue_thaw at gobject.c:290
 #8 g_object_thaw_notify at gobject.c:1293
 #9 gs_plugin_loader_run_refine at gs-plugin-loader.c:312
 #10 gs_plugin_loader_run_popular at gs-plugin-loader.c:539
 #11 gs_plugin_loader_get_popular_thread_cb at gs-plugin-loader.c:1274
 #12 g_task_thread_pool_thread at gtask.c:1215
 #14 g_thread_proxy at gthread.c:764