title: Intellij IDEA: Breakpoint not being hit, and is shown greyed out
body: <p>Running JDK 1.7 on Mac OS X and suddenly breakpoints on my project are not working, and they are appearing greyed out.  They were working earlier today, so not sure what I have done to cause this.  I am using Intellij 13.1.3.  Why would breakpoints stop working like this?</p>
  
  <p><img src="https://i.stack.imgur.com/TdYYH.png" alt="Grey, non-functioning breakpoint in Intellij 13"></p>