When a submitButton is present in a Shiny application, it causes all the inputs on the page to not send updates to the server until the button is pressed.

Because a submitButton alters the behavior of all other inputs on the page, we generally recommend not using submitButton, and using actionButton instead. In most cases, it is best not to use submitButton, but instead to use actionButton, since it allows finer-grained control over which inputs will trigger re-execution of code. See the actionButton demo in the gallery for more information.