Activity explorer page content doesn't show up

Hi,
Since adding a page to capella activity explorer using the vpdsl didn’t work for me, I decided to follow the tutorial which is accessible via the following link:
https://wiki.eclipse.org/images/6/66/Activity_Explorer-1.0.0.pdf
The problem is that when I click on the page icon in the workflow view I get a blank page rather than the page content (section and activities, in addition to previous and next pages). (see screenshots)
Can anyone explain this behavior please?

workflow.PNG
blankpage.PNG
pageContent1.PNG
workflow.PNG
blankpage.PNG
pageContent1.PNG