> That’s why it’s common to see radio buttons containing checkmarks The radio-buttons prior all included an additional inner circle to imply a selected state.

> That’s why it’s common to see radio buttons containing checkmarks The radio-buttons prior all included an additional inner circle to imply a selected state. You can't just have empty and filled, since filled could be off, and empty could be a filled circle over a filled circle, in other words on. La, the prior was only good design because it was common design.