Code review comment for lp:~bratsche/oif/evince-drag-selection

Now, for the actual functionality implemented in this branch. I'm getting inaccurate selections of text. Here are the steps I'm taking:

 1. double tap to get selection mode
 2. drag my finger down to select text
 3. text selection is off by a little over a line in some areas, a few words in other areas, and several lines in others.

I thought this might be due to the finger overlapping the width of a line, so I zoomed in very large and tried it. In some instances, this actually made the results worse (the selection would jump several lines from where I actually touched).