Products backend form not appearing

Hi,

I am creating my own Articles module, based on the products module. I have copied the ProductDefinitions class into my project, renamed the necessary classes. However when I visit the /sitefinity/content/Articles page, then I all I see is an empty page - see attachment. I debugged the code and all functions are being called to add the definitions into the UI. I checked the logs but the folder is empty. I have compared all classes from the Products project with my project and can't see any difference. I am not sure what else to look for. Maybe somebody else can help me out here?

Thanks