Rocks Great ! Thanks from Brazil !

Does nothing, WTH?

Display an empty box, and do nothing at all.

Working fine with Waterfox 56.2.1 (56.2.0.53) on FreeBSD-CURRENT.

Ideally suited to situations such as this:

https://github.com/MrAlex94/Waterfox/issues/664#issuecomment-397975609

bad

一个600px*262px的区域，一直在可视窗口正中间显示，这也就算了，那么大的功能块居然不能移动，挡住我浏览网页，果断卸载,这个插件用户体验一点也不好;
A 600px*262px area has been shown in the middle of the visual window, and that doesn't matter, so big blocks of functionality can't move, stop me from browsing the web, and uninstall it decisively, and this plug-in user experience is not good at all;