There are breadcrumbs across the debugger's toolbar for quick always available access, or there is a tab to display the whole stack at once next to the sources tab on the left sidebar.

breakpoints are a bit of a hit or miss, especially when callbacks are involved.

If you have a test case / url / steps to reproduce, please file a bug: https://bugzilla.mozilla.org/enter_bug.cgi?product=Firefox&c...

We can't fix what we can't detect.

So kudos to them for all the hard work.

Thanks :)