Description of problem:
I was removing a duplicate icon that I had just added to the top panel in MATE.

Version-Release number of selected component:
mate-panel-1.5.6-1.fc18

Additional info:
backtrace_rating: 4
cmdline:        mate-panel
crash_function: calculate_minimum_height
executable:     /usr/bin/mate-panel
kernel:         3.8.11-200.fc18.x86_64
uid:            1000
ureports_counter: 1

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 calculate_minimum_height at clock.c:380
 #1 use_two_line_format at clock.c:407
 #2 get_updated_timeformat at clock.c:446
 #3 update_timeformat at clock.c:479
 #4 show_date_changed at clock.c:1883
 #5 g_cclosure_marshal_VOID__STRINGv at gmarshal.c:1004
 #6 _g_closure_invoke_va at gclosure.c:840
 #9 g_settings_real_change_event at gsettings.c:288
 #10 ffi_call_unix64 at ../src/x86/unix64.S:75
 #11 ffi_call at ../src/x86/ffi64.c:486