If you happen to have a link to a page where the Firefox devtools are not doing what they should, and happen to remember which version of Firefox you were running at the time, I would very much appreciate that!
That bug is marked as a duplicate of a bug that's been fixed for close to a year now. So either you're seeing a different issue, or your recent experience wasn't all that recent. If it's the former, I really would appreciate more details so we can fix it; if it's the latter, give it another shot. ;)
Maybe I should go more into detail. The problem we had was that some charts and graphs in our application was not showing up only on Firefox ESR 38.3. Examination of the problem revealed that rickshaw was not loaded. The console had thrown an error from rickshaw.js saying that d3 was not loaded. But rickshaw.js was not available in debugger console !
The reason I did not raise a bugzilla was because the issue was intermittent ( ! ) and also I cannot share the whole application user interface with outsiders yet. Anyway, my working conjuncture is that these files are loaded from callbacks of AJAX requests and the problem happens when the callback for loading rickshaw fires before the callback for loading d3 has had a chance to fire. We ended up loading d3 manually as a workaround. But it is important to show rickshaw.js in the debugger since it enables us to set breakpoints there.
Hmm. The bug you link to was fixed in 36, so in 38.3 you're seeing a different problem.
I understand the difficulty in filing bug reports on pages that you can't show people yet. If you get to a point where you _can_ show it to people (even just a limited set, not the whole world), and you're still running into the problem, the bug report would be very much appreciated.
