Add a divider item

[calypso15]

The basic idea is just a non-interactable horizontal line to help visually group items. Collapsible groups would be perhaps a better, but more labor intensive option.

[elchininet]

Hi @calypso15,
That would not be an easy feature to implement, in part because of this but also because right now order option expects to have only items related to a sidebar anchor and there are a lot of code that depend on this. But it is something good to take into account during a refactoring of the code.