Do you have a URL we can use to test the issue? It could be hard to work on unless we're able to reproduce the problem.
We can't really do anything with this bug unless we have a way to reproduce the issue. I will leave the bug open for now, but unless we get steps to reproduce, I will eventually have to close it as unactionable.
If this turns out to be an actual bug, then it's breaking basic debugger functionality that should just work. Marking this as P1 to remind myself to get back to this asap, either to fix the bug if STR have been provided, or close it otherwise.
Well i want to help you get the information needed. but the hard part is that i can't reproduce it consistently. It happend initial when i was trying to gather the info on this page. I tried it in this pages comments.js line 53. The first time it didn't stop. But while i was trying different scenarios (inspector snapped in the firefox window. inspector free of the firefox window) it suddenly paused. And after that it just seems to work. Even after closing firefox. I have no hard numbers but in general i notice this more on local web pages i am developing (hosted on 127.0.0.1). And i always have the inspector on a separate screen. Let me know if this helps or what i should supply to help you.
Might it have something to do with - formatting the code in the debuggger - reloading the page ? If you see it again, could you copy and paste any errors that seem relevant from Tools - Web developer - Browser console?
Removing priority as this is not actionable. If you can attach a test case where we can reproduce it (even if it's inconsistent) we will look into it.
Unfortunately I don't think there's enough info here to make progress. If you can think of more specific steps so that one of us can reproduce, please reopen!