1258659 - Setting height: 'auto' renders with zero height until browser is resized

Status: NEW

(Core :: Layout, defect)

Description

[Thomas Zimmermann]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36

Steps to reproduce:

Tested on Mac OS X with Firefox 44.0:

1. Given the HTML snippet in this jsfiddle: https://jsfiddle.net/vvy30jpg/11/
2. It has two 'wrapper' divs with 100% height each and one 'outer' div without any styles.
3. The text 'Test' is initially shown correctly.
4. Click on the button 'Set Height to auto' This sets the 'outer' div's height first to 0, then to 'auto' and queries the offsetHeight in between.


Actual results:

The text 'Test' is not visible any more. If you inspect the DOM, you see that all 3 divs are rendered with zero height. 
This changes if you, for instance, resize the browser window. Then, the rendering is correct again.


Expected results:

The 'Test' text should be visible.

I tried to minimise the example as much as possible, but it seems that two wrapper divs with 100% height each are required, as is the offsetHeight querying. If you comment out this line, it will work.

Comment 1

[Alice0775 White]

Regression range: 
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=a12d1b2e6e17&tochange=09878dde0cc8

Comment 2

[Xidorn Quan [:xidorn] UTC+11]

I wonder whether this is a duplicate of bug 1242172.