It's pretty crucial that we get an attribute that lets us rotate the tooltip of a <Button> element.

Right now there isn't any way (that I can see) to control the rotation of a button's tooltip, which means that when it is displayed wrong (text backwards in my current case), we can't fix it. Adding rotation on the <Button> element doesn't change the rotation of the tooltip (or even its position around the button, which is weird imo). So we need this attribute pretty badly.