I'm not sure this is a situation we can support - the canvas is not designed to be bigger than the window, and if you use a fullscreen-in-browser setting there's no good way to integrate with the browser scrollbar. To be honest Construct 2 is designed as a game creator and not a website creator, so I don't want to get involved in adding features to design websites. You should be aware of severe shortcomings from designing websites like this: it's often inaccessible, will not be viewable on old browsers, it's unsearchable, untranslatable, does not integrate with browser forward/back, has no URLs to specific pages, cannot copy/paste text out the page, Google cannot index it so you'll get a rock bottom pagerank, etc. etc. Many of these issues cannot be fixed at all. Because of this I don't recommend making websites in Construct 2 and we probably won't fix any issues that crop up in trying to make websites. I highly recommend going back to HTML!