subscriber-view: iter the single day table

When we modify an event, the start date may change
and there is no way to retrieve it back. Since we're
relying on the start date to get the cell number and,
remove the widget, it leads to a crash because the
widget is not removed.

Fix that by brute-forcely search the widget in the
correct table.

src/gcal-subscriber-view.c

@@ -250,14 +250,48 @@ gcal_subscriber_view_remove (GtkContainer *container,
             }
           else
             {
-              guint cell_idx = gcal_subscriber_view_get_child_cell (GCAL_SUBSCRIBER_VIEW (container), GCAL_EVENT_WIDGET (widget));
+              GHashTableIter iter;
+              gpointer key, value;
 
-              aux = g_hash_table_lookup (priv->single_cell_children, GINT_TO_POINTER (cell_idx));
-              aux = g_list_remove (g_list_copy (aux), widget);
-              if (aux == NULL)
-                g_hash_table_remove (priv->single_cell_children, GINT_TO_POINTER (cell_idx));
-              else
-                g_hash_table_replace (priv->single_cell_children, GINT_TO_POINTER (cell_idx), aux);
+              /*
+               * When an event is changed, we can't rely on it's old date
+               * to remove the corresponding widget. Because of that, we have
+               * to iter through all the widgets to see which one matches
+               */
+              g_hash_table_iter_init (&iter, priv->single_cell_children);
+
+              while (g_hash_table_iter_next (&iter, &key, &value))
+                {
+                  GList *aux;
+                  gboolean should_break;
+
+                  should_break = FALSE;
+
+                  for (aux = value; aux != NULL; aux = aux->next)
+                    {
+                      if (aux->data == widget)
+                        {
+                          aux = g_list_remove (g_list_copy (value), widget);
+
+                          /*
+                           * If we removed the event and there's no event left for
+                           * the day, remove the key from the table. If there are
+                           * events for that day, replace the list.
+                           */
+                          if (aux == NULL)
+                            g_hash_table_remove (priv->single_cell_children, key);
+                          else
+                            g_hash_table_replace (priv->single_cell_children, key, aux);
+
+                          should_break = TRUE;
+
+                          break;
+                        }
+                    }
+
+                  if (should_break)
+                    break;
+                }
             }
         }