You would be surprised if you know that most of the time spent for creating the buttons, is spent in adding the tooltips to them! We might want to write a faster version of the original
https://github.com/suda/tool-bar/blob/937f75719a1002af5b207c073b6e45dd82617f44/lib/items/tool-bar-button-view.js#L121

https://github.com/atom/atom/blob/e4b9c1e0815c5c07514a0649e7ebb9b5226a2931/src/tooltip-manager.js#L113-L181

For 30 buttons, this becomes ~6ms.

Which is almost the same as the whole time spent on the buttons:

I am going to port the function to our package and see if I can write a faster version.