Description of problem:
added a extension

Version-Release number of selected component:
cinnamon-1.9.1-12.fc19

Additional info:
reporter:       libreport-2.1.5
backtrace_rating: 4
cmdline:        cinnamon --replace
crash_function: g_realloc
executable:     /usr/bin/cinnamon
kernel:         3.9.9-301.fc19.x86_64
runlevel:       N 5
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #1 g_realloc at gmem.c:224
 #2 g_array_maybe_expand at garray.c:785
 #3 g_array_set_size at garray.c:561
 #4 stack_do_window_additions at core/stack.c:867
 #5 stack_ensure_sorted at core/stack.c:1010
 #6 get_default_focus_window at core/stack.c:1483
 #7 meta_stack_get_default_focus_window_at_point at core/stack.c:1556
 #8 meta_screen_get_mouse_window at core/screen.c:2056
 #9 ffi_call_unix64 at ../src/x86/unix64.S:76
 #10 ffi_call at ../src/x86/ffi64.c:522