React warning when pressing "Share" button

When pressing the "Share" button for the first time, you get this React warning in the console:
```
Warning: Failed form propType:
You provided a `value` prop to a form field without an `onChange` handler.
This will render a read-only field. If the field should be mutable use `defaultValue`.
Otherwise, set either `onChange` or `readOnly`.
Check the render method of `HoverMenu`.
```