I am working on personalization with AEM 6.1. I created a brand page under the campaign folder. Under the brand page, I have created a campaign and under that campaign, I have created several pages using the offer page template which is provided in built with AEM.
Even though the content in the offer page exceeds the height of the screen, the scroll bar is not visible on the page. I verified it on a vanilla AEM 6.1 author instance on geometrixx pages, and it is getting reproduced there also.
Steps to reproduce:
Open the page /content/campaigns/geometrixx/scott-recommends.html
Drag an slideshow component in the parsys and edit the component. You can see that the dialog of the slideshow component exceeds the page height, but still there is no scrollbar on the page. You need to zoom out (ctrl + -) to view the dialog properly.
Also when you add an image to the slideshow component and click ok (by zooming out the page), the image is not visible completely on the page.