It would be great if opening a modal dialog (e.g. lightbox like keyboard shortcuts or smilies selector) would stop me from interacting with the topics / posts in the background. So, no scrolling or anything.
The same goes for scrollable popups like the user menu or even the preview window when writing a post. When there’s a scrollbar visible, scroll event shouldn’t bubble up the event chain and start scrolling the topic list or posts.
Scrolling in the user menu:
Scrolling in the post preview:
Facebook does a great job in both cases:
- Open an image in a lightbox. You can’t scroll the posts in your timeline that are still visible behind the image.
- Open your notification or message popup menu and scroll to the bottom of those lists. Even if you are at the end of those lists, the posts in your timeline don’t start scrolling.