Panel (WelcomePanel) contains a form. That form is not added explicitly to the page (HomePage) but is provided by an implementation of IComponentResolver configured for the app.
The panel and the form display without a problem which indicates that the component resolver has correctly resolved the component but the form does not function correctly.
When user clicks on a form a message appears saying that a component could not be found.
If you uncomment the 'add' in HomePage.onInitialize() to explicitly add the WelcomePanel (instead of relying on the component resolver to do it) then the form functions correctly.