There could be multiple reasons.
In most cases, it is the connection between the widget and the text box. Click Here and read this article to see what may cause such issue.
There is also something else that I see on your project and that is the "Double Arrow" icon next to the breakpoint bar, it is pointing inside, meaning that you are having a maximum width on the page, so click on it and see if that make any changes.
If you could not get it to work, send it to firstname.lastname@example.org and we will see what causes the issue and will fix it for you.