I reported an issue if LFG Bulletin Board in Sexymap where it would not be hidden until mouseover like other addon buttons. I got the reply that the minimap button needs to be implemented using LibDBIcon to play nice with other addons.

We still dont bundle LibDBIcon in the addon ourselves, but with #302, you should be able to take advantage of LibDBIcon if you have any other addon that does include it (Sexymaps, leatrix, dragonflight ui, etc).