The widget "Upload File" it's not working like expected. I've set the Enabled property as False and visually it's actually disabled (the widget is grey) but when I click on it, I can actually upload a file. How can I solve this problem?
You can put a pointer-events: none when it is disabled (try to find the classes on the HTML that gives the disable style to the upload widget and with that classes you put the pointer-events: none), and you can do a client and server validation to check if it was uploaded something, and if that's the case you can remove the uploaded file and give a feedback message.
You can also use an if widget to hide the upload widget.