Upload and ProgressBar not shown

When I try to design a page with an upload and a progress bar (for showing some processing progress), these two elements are not shown.
The DOM shows only

<vaadin-upload target="VAADIN/dynamic/resource/1/8fd128ae-bade-44ca-85ca-dbab1becdf59/upload"></vaadin-upload>

This happens with Vaadin 14.0.11 and npm.

This sound an awful lot like [this]
(https://vaadin.com/forum/thread/17765421/14-npm-mode-com-vaadin-flow-component-internal-componentmetadata-front) ([related github issue]

Basically, this happens when you don’t have any View that uses an Upload or Progress Bar directly. Either you add the Upload using reflection, or other generic methods.
in the github it says this will be fixed in 14.1

If you need a fix now, for me it worked when I declared a field of that type in any view with a @Route. That field doesn’t have to be used.

private Upload unusedUpload;
private ProgressBar unusedProgressBar;

Yes, Kaspar, that sounds right.
Thanks to that thread I could resolve my problem with the annotation

@Route(registerAtStartup = false)

on the class.

It’s a shitty workaround but better than not working at all.