STR, using Nightly (non-e10s) on OS X 10.9.5: * Have a FirefoxOS device with Wifi Debugging enabled which is NOT pre-authorized for WebIDE via "scan and remember". * Open Activity Monitor to keep an eye on CPU usage. * Open WebIDE in Nightly. * Click on the device name under WI-FI DEVICES - the Client Identification sheet with the big QR code appears * Wait a bit; do NOT scan the code to confirm. Note that Nightly's CPU usage has shot up to something over 150%. * Click Cancel to dismiss the Client Identification sheet. Note that the spinner in the WebIDE title area stays, and Nightly's CPU usage remains high.
Hmm, I wasn't able to reproduce this on my first attempt. Are you able to cause this every time? How long do you need to wait? What is "a bit" in this case?
(In reply to J. Ryan Stinnett [:jryans] (use ni?) from comment #1) > Hmm, I wasn't able to reproduce this on my first attempt. Are you able to > cause this every time? How long do you need to wait? What is "a bit" in > this case? I just re-tested this using current Nightly (restarted in Safe Mode), and it reproduces reliably for me. Note that with Firefox WebIDE open, I see very high CPU usage whenever it's displaying a prompt sheet and showing the titlebar spinner (e.g. click on Remote Runtime, so it displays the hostname:port prompt; within a few seconds, Activity Monitor shows Nightly as using around 150% CPU). This seems to be "feature" of the animated spinner. But in the Remote Runtime case, when I click Cancel to dismiss the sheet, the spinner goes away and is replaced by the Play / Stop / Wrench icons. In the case of clicking on my Aries device under Wi-fi Devices, so that it displays the Client Identification prompt with the QR code, the spinner similarly causes 150% CPU usage. But in this case, clicking the Close link at the top left (sorry, it's called Close, not Cancel) to dismiss the sheet -- in WebIDE, I mean, not the Cancel button on the device -- does NOT make the spinner go away; it stays there (consuming CPU) until some other action causes the titlebar/top panel area to be updated. I see that I said this slightly wrong above: > * Click Cancel to dismiss the Client Identification sheet. Note that the spinner in the WebIDE title > area stays, and Nightly's CPU usage remains high. Sorry, that was misleading, and I guess is probably why you failed to reproduce. Specifically, if you hit Cancel on the device at that stage, the WebIDE window handles things OK. It's clicking Close in the prompt sheet within WebIDE that fails to remove the spinner.
WebIDE triage. Filter on TRIAGE-JD201705 For the record, just reproduced trying to debug a regular android device, so the bug is still valid.