Focus ripple does not extend entire button

Question

Whenever I hover or click on a Material UI Button the ripple effect covers the entire button. However, when using tab and tabbing into the button, only a small portion of the button gets the ripple effect. How can I get this ripple to expand to the entire button?

I am adding in style this way, and tried adding a hover style here :

const StyledButton = withStyles({
  label: {
    textTransform: 'none',
  "&:hover": {
      border-radius: "10px"
    }
  }
})(MuiButton);