Last modified: 2014-07-28 20:48:45 UTC
There is a 5-10pt dead area when starting a scroll. To reproduce, simple begin a scroll in either direction very slowly. You'll notice that your finger needs to move the height of the vertical space between lines before the content scrolls. This is counter to iOS' default behaviour of immediate scroll.
Known issue. Has to do with the fail-over relationship between the horizonal (toc) gesture recognizer and the vertical (web view) recognizer. I think we can tune these better to help with this issue.
Good catch though! :)