customizable "folder" that is always open - like opera "speed dial" ?

[Ryder17z]

Like title suggests, I would like to have a folder that is always open (overriding the setting to auto-close folders if enabled), like the "opera speed dial" on fresh install where I can permanently pin items.

Sure, i can stuff items into "Other bookmarks" and leave it open, but it doesn't feel right to do so.

Mockup: image