XML fragment directory issue
Maybe I implemented this wrong so I'm posting this to see if maybe thats the case. In the Metadata.view.xml file the buttons reference the various fragmentName files with "./fragment". I was getting errors saying "view//fragment" not found. I simply edited the string and removed the dot ".". This resolved the errors.
Image of project folder directory:

Hi, this app is running as expected because the code is 1:1 used in the cloud as demo without any changes?!?
It looks like you imported the project into eclipse! The preview does not take care on the folder webapp!
The Web IDE builds a custom version into dist folder and serves it without webapp. Inside Web IDE webapp is proxied and removed by Web IDE.
If you serves it from eclipse, the easiest thing would be pushing up everything below webapp one level or to change the proxy for previewing.
Regards Holger