Rated 5 out of 5 stars

希望能做些别的事情, 只用来关闭, 好像不合适, 可以定义成刷新页面
等其他事情

Yes, but on the other hand, I used to use TabMixPlus, for 2 reasons only. 1: double click to close tab. 2. adjust tab width. The issue is, why would I install such a big addon that slows FF down for these two trivial reasons? That's why I made this small DCCT addon to replace it (for myself at least). If I add more and more functionality, DCCT will become more like TMP. You can try check if TMP is actually more useful for you, or find another small footprint addon that does what you want alongside DCCT.