User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:59.0) Gecko/20100101 Firefox/59.0 Build ID: 20180226180053 Steps to reproduce: 1) Go to a javascript line in debugger tab. 2) Try to keep a break point. Actual results: Break point appeared and disappeared. Expected results: Breakpoint should be added and execution point should stop at that point when I call it.

I tested this issue on Mac OS X 10.12 with FF Nightly 60.0a1(2018-03-04) and I can't reproduce it. Vallinayagam, can you please install FF Nightly (https://nightly.mozilla.org/) and retest this issue?

(In reply to ovidiu boca[:Ovidiu] from comment #1) > I tested this issue on Mac OS X 10.12 with FF Nightly 60.0a1(2018-03-04) and > I can't reproduce it. > Vallinayagam, can you please install FF Nightly > (https://nightly.mozilla.org/) and retest this issue? Hi ovidiu, Thanks for responding to my query. In reply to your comment, I have attached my error video that occurs in Firefox Developer edition browser as of now. I am not familiar with firefox Nightly. Is it necessary that I should try firefox nightly? Regards, Vallinayagam T

You only need to install FF Nightly version and try to reproduce the issue, Nightly is the same as FF release. Btw I can't see the attached video, maybe you can use https://streamable.com/ to upload the video.

Hi ovidiu, Thanks for the update. I have uploaded my video using https://streamable.com/ and the link is https://streamable.com/sdrn8 Please forgive me for my ignorance. In the docs, it is mentioned that Firefox Developer edition is exclusively designed for developers and firefox nightly is the future web browser that would replace firefox in the near future. I want to know about the bug in firefox developer edition and not in the firefox nightly. I am going to try firefox nightly too. If I find the same error in the firefox nightly, I will report it. But,please guide me in the firefox developer edition issue. Regards, Vallinayagam T

I have exactly the same issue with Firefox Developer Edition und MacOSX v10.11.6. I experienced it in v60 and v61.0b13.