Most text files are too long to fit on the display screen, and some individual text lines are too wide. Accordingly, the panes in which the versions appear have both vertical and horizontal scroll bars. Scrolling of the panes is synchronized automatically. Line numbers appear at the left edge of each pane.
For a text file that contains hundreds or thousands of lines, there may be only a few difference sections (added, deleted, or revised), separated by large unchanged sections. The Diff tool provides both navigation buttons on its toolbar and a difference map for direct access to a particular difference section.
To the right of each pane, there's a difference map that shows the relative locations and sizes of all the difference sections. The maps use the same color-coding (see
Color-Coding of the Contributor Versions on page 229) as the difference sections themselves. Click on any colored area within a map to scroll both panes directly to the corresponding difference section. (Actually, you can click anywhere in the difference map; the panes will scroll to that location, even if the files are identical there.)

Using a difference map merely scrolls the panes; it does not affect which difference is the current difference. After you jump to a particular location, click the difference section in either pane to make it the current difference.