Selecting text in editor with keyboard not working properly

Selecting text in the editor with Shift+Up/Down is not working as it should.

For example, go to http://community.jboss.org/docs/DOC-14105 and open to edit it. Set the cursor before "Following" word in 1st paragraph. Now do Shift+Down a couple of times, the result is that the first line is not selected, but the ones after they are.