Mouse-drag scrolling doesn't work in article edit

Reproduction steps:

1. In the latest Chrome browser, use the Edit link at the top of a page that is long enough to have a scroll bar of fewer than 30px high
2. using the mouse cursor's click and drag try to scroll the page content

Expected:

Article content scrolls

Actual:

The page title content gets selected and the content isn't scrolled.

Scrolling using the mouse wheel works. After scrolling using the mouse wheel the mouse can then be used to drag the scroll bar

The issue doesn't happen in IE

I'm not sure if this happens with other articles made using templates other than the default blank template.

Problem:

The 'editor-precursor' div extends over the top of the scroll bar preventing it from being selected. Manually limiting the width of the div to 95% seemes to fix the issue