[Affected versions]: Firefox 54.0b2 (Build Id:20170424145525) [Unaffected versions]: Firefox 55.0a1 (Build Id:20170427030231) Firefox 53.0 (Build Id:20170413192749) [Affected platforms]: Windows 10 64bit Mac 10.11.6 Ubuntu 14.04 64bit [Steps to reproduce]: 1.Launch Firefox with a clean profile. 2.Access the https://www.mozilla.org/en-US/ website. 3.Right Click anywhere. 4.Click Inspect Element. 5.Try to pick a specific element from the page (ex. Stand Up For Encryption). [Expected result]: The Stand up For Encryption can be inspected. [Actual result]: The Stand up for Encryption element cannot be inspected. [Regression range]: This is already fixed in latest Nightly. [Additional information]: Please note that this issue is reproducible only by using a clean profile and when using the inspector for the first time. This issue is not reproducible after restarting the inspector or after refreshing the webpage.

Please access the following link in order to see more details about this issue: https://drive.google.com/open?id=0B94iuIVMr-TEQ3Q2RXZjaVRvYnc

Hey emilghitta, do we know which bug / patch fixed this issue on Nightly?

Hi Mike ! I couldn't find the bug that fixed this issue on Nightly because this is very time consuming for me ( I have tested with old Nightly from 2014 and with the latest Nightly and both of them turned out to be good builds). I have managed to reproduce this issue on Aurroa and managed to find this pushlog using mozregression: pushlog_url: https://hg.mozilla.org/releases/mozilla-aurora/pushloghtml?fromchange=d56c36ff0b8bc34183f056866de81a6a61c782ec&tochange=189ed7b2306fcf0a7683df6959b78fdb94bb34e7 Looking at the pushlog, i suspect bug 1349275 caused this issue to appear in Aurora. Let me know if this helps!

Got a sec to look at this possible regressino from bug 1349275, zer0?

DevTools bug triage (filter on CLIMBING SHOES)

I wasn't able to reproduce at first attempt, I'll test deeper once I've complete the bugs I'm working on for the CSS Grid.

I believe this is a duplicate of bug 1373994, that is fixed in 55. Feel free to reopen if that is not the case!