1257788 - Browser randomly hangs for short periods when adding lots of nodes into an element with 'visibility: hidden'

Status: NEW

(Core :: Layout, defect)

Description

[Paul Oiegas [:poiegas], PM for (Ecosystem QA, Services QA, WebCompat QA, Ads QA, and Solo QA teams)]

Attachment: Add_nodes_testcase.html

[Affected versions]:
- Firefox 45.0, Build ID 20160303134406
- Nightly 48.0a1, Build ID 20160317030235 (without e10s activated)

[Affected platforms]:
- Windows 7, Windows 10
- Mac OS 10.11 
- Linux 14.04

[Prerequisites]:
- Disable e10s feature if the browser under test supports it.

[Steps to reproduce]:
1. Open the browser and the attached testcase.
2. Spam click the "Add Content" button (I used an auto clicker software).
3. Observe the browser behavior while the content is added.

[Expected results]:
No matter how long the button is spammed, the browser remains stable and responsive.

[Actual results]:
Browser randomly hangs  for short periods (not responding state) when spamming the "Add Content" button.

[Notes]: 
- This behavior usually occurs when Firefox / Nightly process reaches values between 400MB and 900MB of RAM memory used.
- I have tried to reproduce this with e10s enabled but after 2GB of RAM memory used, didn't encountered any hangs.

Comment 1

[Timothy Nikkel (:tnikkel)]

visibility: hidden elements still take up space, they just don't display, and descendants can be visibility: visible, so layout still needs to be performed.