Hi there. I found this behaviour in my main site and was unsure of what was causing it so I created the dev site prtest.wpmudev.host. Bottom line is that if both Jetpack and Smartcrawl are activated then the admin "Post" list view is broken. Instead of the Title field having a mouseover with a list of possible actions you get one column which is one character wide making the list summary post view virtually unreadable. The behaviour isn't related to the theme. If you deactivate either Smartcrawl or Jetpack the view returns to normal.