I closed the calendar window.

Very shortly after that I got this segv :-)

I assume we don't shut-down a timer correctly:

Program received signal SIGSEGV, Segmentation fault.
0xb07120a0 in e_calendar_view_get_tooltips (data=data@entry=0x14aa0fa0) at e-calendar-view.c:2023
2023            g_return_val_if_fail (E_IS_CALENDAR_VIEW (data->cal_view), FALSE);
(gdb) bt

+ Trace 232928

(gdb) p *data
$1 = {get_view_event = 0xb071f480 <tooltip_get_view_event>, cal_view = 0xd2357a0, day = 0, event_num = 2}
(gdb) p data
$2 = (const ECalendarViewEventData *) 0x14aa0fa0
(gdb) p *data->cal_view
$3 = {parent = {container = {widget = {parent_instance = {g_type_instance = {g_class = 0x45454545}, ref_count = 1162167621, qdata = 0x45454545}, 
        priv = 0x45454545}, priv = 0x45454545}, priv = 0x45454545}, in_focus = 1162167621, priv = 0x45454545}

HTH