Index: trunk/src/libcschem/operation.c
===================================================================
--- trunk/src/libcschem/operation.c	(revision 1223)
+++ trunk/src/libcschem/operation.c	(revision 1224)
@@ -93,7 +93,9 @@
 	csch_undo_remove_t *u = uundo_append(&sheet->undo, &undo_remove, sizeof(csch_undo_remove_t));
 	u->obj = obj;
 
-TODO("check if parent exists");
+TODO("remember parent in u; handle when parent gets empty");
+	csch_cobj_rtree_del(obj->sheet, obj);
+	assert(obj->parent != NULL);
 	htip_pop(&obj->parent->id2obj, obj->oid);
 	gdl_remove(&obj->sheet->active, obj, link);
 	obj->parent = NULL;