Since you're only ever accessing .id, you may want to change this to DOM.uid().id

thanks for the tip

What is the purpose of the negative left offset?

If you didn't want to use `display: none` to hide it and still have it be visible to screen readers you can use this approach instead.

If you namespace the listeners, it'll be easier for the calling chart to style the mouseover point or attach an additional mouseover listener without clobbering the tooltip one: https://github.com/gka/d3-jetpack/blob/master/src/attachTooltip.js#L12-L16 https://github.com/gka/d3-jetpack#attachTooltip

Good idea, thanks!