rem: proplist_t value, int *modified, int flags)
add: proplist_t value, int flags)
context: insertAttribute(proplist_t dict, proplist_t window, proplist_t attr,                proplist_t value, int *modified, int flags){    proplist_t def_win, def_value=NULL;    int update = 0;    if (!(flags & UPDATE_DEFAULTS) && dict) {        if ((def_win = PLGetDictionaryEntry(dict, AnyWindow)) != NULL) {            def_value = PLGetDictionaryEntry(def_win, attr);        }    }    /* If we could not find defaults in database, fall to hardcoded values.     * Also this is true if we save defaults for all windows     */    if (!def_value)        def_value = ((flags & IS_BOOLEAN) != 0) ? No : EmptyString;    if ((flags & IS_BOOLEAN))        update = (getBool(value) != getBool(def_value));    else {        update = !PLIsEqual(value, def_value);    }    if (update) {        PLInsertDictionaryEntry(window, attr, value);        *modified = 1;    }}