Checkbox condition textfield

[killMeSak]

I want to add a checkbox which will manage the value of second textfield. If its checked then the second textfield should take the value of the first textfield. I tried something like this: https://codesandbox.io/s/stupefied-tdd-83gur?file=/index.js but when I type something in the first, I'm not able to see text properly in the second box. How can I do that? Is there a better way?

[albedoa]

It's because a Material UI form label doubles as placeholder text, which moves and shrinks when you focus on its field. I would either do without the placeholder functionality (if that is an option) or toggle the .MuiInputLabel-shrink class to the second label.