title: Eclipse debugger hits breakpoint but I can't move it
body: <p>I've used Eclipse for a long time so I'm fairly familiar with the debugger. On my current project we are doing browser automation with Selenium. Recently I've been having an issue where, when debugging, I hit one of my breakpoints and I am unable to step forward or continue - I can only stop. The other step buttons are disabled and grayed out. I'm completely confused as to why this happens (not super familiar with exactly how debugging happens). Once in a while it works but I can't tell why it worked suddenly. After one successful run it goes back to being unresponsive after hitting a break point. I thought it might be a multi-thread issue but I'm just guessing. I tried terminating and removing the running threads but that doesn't seem to help.</p>
  
  <p>Any idea why this is? I'm using Eclipse Java EE IDE Mars 4.5.1.</p>