 <p>The Firebug Working Group is working on fixing this problem in <a href="https://code.google.com/p/fbug/issues/detail?id=7301" rel="nofollow">issue 7301</a>. The issue is currently missing a reproducible test case. So any tips that help to fix this problem or a simple test case should be posted there.</p> <p>You and nmaier already named the workarounds known so far, which are Firebug menu > <em>Options</em> > <em>Reset All Firebug Options</em> or deleting the breakpoints.json file manually from the profile folder followed by a browser restart.</p>