// Fix up stair markers.  The travel information isn't hooked up
    // until after we change levels.  So, look through all of the stairs
    // on this level and check if they still need the stair flag.
    for (unsigned int x = 0; x < GXM; x++)
        for (unsigned int y = 0; y < GYM; y++)
        {
            unsigned int tile = env.tile_bk_bg[x][y];
            if (!(tile & TILE_FLAG_NEW_STAIR))
                continue;
            const coord_def gc(x,y);
            int object = grd(gc);
            if (!is_travelable_stair((dungeon_feature_type)object) ||
                travel_cache.know_stair(gc))
            {
                env.tile_bk_bg[x][y] &= ~TILE_FLAG_NEW_STAIR;
            }
        }