GtkTreeModel *tm = gtk_tree_view_get_model (GTK_TREE_VIEW (ml->var_view));
g_ptr_array_add (ml->layer, tm);
g_signal_connect_swapped (tm, "row-inserted", G_CALLBACK (refresh_view), ml);
GtkTreeModel *tm = gtk_tree_view_get_model (GTK_TREE_VIEW (ml->var_view));
g_ptr_array_add (ml->layer, tm);
g_signal_connect_swapped (tm, "row-inserted", G_CALLBACK (refresh_view), ml);