[Suggestion][UI] Booksmarks pane buttons

In Bookmarks pane, “…” button should perhaps be “+”, to match the “-” button. Otherwise, a bit confusing and makes “-” more dangerous because meaning not so obvious.
Or need to add “+” and change function that “…” does?

Scrivener beta (19429) 20 Nov 2017
Windows 10 Pro 64 bit 10.0.15063

I see that in Scrivener 3 for Mac OS X, the gear (options?) icon is used instead of “…” and no “+” is offered, so I guess disregard this. I"ll adapt.