force scrollbar

platform:  # supported: 2.2.4, 2.3.1
backlogs:  # supported: 1.0.3
ruby:  # supported: 1.9.3, 2.0.0

The stories in the backlogs can have some quite big "tooltips". So when someone hovers over the issue number the info box could be bigger than the display an the browser will add a scrollbar. If the user has placed its mouse at the right position it will no longer be above the issue number and the tooltip will disappear.
That makes the interface a little bit unstable.

I fixed it with always displaying the scrollbar, so it can cause no toggling.