when subMaxLevel at 3 level, sidebar will be render many times

[yangyang0507]

RT. when we jump to other page and return to 3 level headline page. sidebar with be render again and again.

[yangyang0507]

经过测试，subMaxLevel在3级以上即会出现 sidebar 重复加载的情况，每次跳入对应的页面就会多加载一次。

如下：