4 files changed, 7 insertions, 2 deletions
diff --git a/calendar/gui/dialogs/event-page.c b/calendar/gui/dialogs/event-page.c
index cb4698fcf3..12931cee09 100644
--- a/calendar/gui/dialogs/event-page.c
+++ b/calendar/gui/dialogs/event-page.c
@@ -779,6 +779,9 @@ update_time (EventPage *epage,
 		end_tt = &implied_tt;
 		*end_tt = *start_tt;
 		icaltime_adjust (end_tt, 1, 0, 0, 0);
+	} else if (!end_tt) {
+		end_tt = &implied_tt;
+		*end_tt = *start_tt;
 	}
 
 	if (start_tt->is_date && end_tt->is_date) {
diff --git a/calendar/gui/dialogs/recurrence-page.c b/calendar/gui/dialogs/recurrence-page.c
index d04d490b3d..77862c6584 100644
--- a/calendar/gui/dialogs/recurrence-page.c
+++ b/calendar/gui/dialogs/recurrence-page.c
@@ -992,7 +992,7 @@ fill_component (RecurrencePage *rpage,
 	if (gtk_widget_get_visible (priv->ending_combo) && gtk_widget_get_sensitive (priv->ending_combo) &&
 	    e_dialog_combo_box_get (priv->ending_combo, ending_types_map) == ENDING_UNTIL) {
 		/* check whether the "until" date is in the future */
-		struct icaltimetype tt;
+		struct icaltimetype tt = icaltime_null_time ();
 		gboolean ok = TRUE;
 
 		if (e_date_edit_get_date (E_DATE_EDIT (priv->ending_date_edit), &tt.year, &tt.month, &tt.day)) {
diff --git a/calendar/gui/dialogs/schedule-page.c b/calendar/gui/dialogs/schedule-page.c
index eafdb91744..516a973751 100644
--- a/calendar/gui/dialogs/schedule-page.c
+++ b/calendar/gui/dialogs/schedule-page.c
@@ -143,6 +143,8 @@ update_time (SchedulePage *spage,
 	if (!end_date->value && start_tt.is_date) {
 		end_tt = start_tt;
 		icaltime_adjust (&end_tt, 1, 0, 0, 0);
+	} else if (!end_date->value) {
+		end_tt = start_tt;
 	} else {
 		end_tt = *end_date->value;
 	}
diff --git a/calendar/gui/dialogs/task-page.c b/calendar/gui/dialogs/task-page.c
index 49f86212c0..ebf279cb22 100644
--- a/calendar/gui/dialogs/task-page.c
+++ b/calendar/gui/dialogs/task-page.c
@@ -2108,7 +2108,7 @@ task_page_select_organizer (TaskPage *tpage,
 	gint ii;
 
 	/* Treat an empty backend address as NULL. */
-	if (backend_address == NULL && *backend_address == '\0')
+	if (backend_address != NULL && *backend_address == '\0')
 		backend_address = NULL;
 
 	default_address = priv->fallback_address;