How to hide Diigo Toolbar? (firefox)

I hide the toolbar, but when i open new window it appeared again. WTF?

How to hide:

1. Install latests version: https://www.diigo.com/tools/toolbar?client=ff
2. Open about:config, search extensions.diigotb.showToolbar, set to false. Done

If the toolbar is already shown, hide it from context menu: