1260882 - Open Sans - (minus) glyph does not render in very specific circumstances

Status: NEW

(Core :: Layout: Text and Fonts, defect)

Description

[zane.miller]

Attachment: Open Sans Font Issue.zip

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36

Steps to reproduce:

We have a page which renders content in an iFrame with a 1px solid border. This content makes extensive use of flex-box for layout. When rendering content into the iFrame the main content is rendered with font-family: "Open Sans", font-size: 15px.

The issue does not occur if any of the following steps are taken:
1. The font is changed
2. The font size is changed
3. The border is removed from the iFrame


Actual results:

When text with the "-" (minus) glyph is rendered the "-" glyph does not appear on the page, though the text is still spaced around where the glyph should appear correctly. The symbol is still present in the DOM and no DOM manipulation/CSS class changes are taking place. Upon scrolling the page the glyph will appear for about 3 seconds and will then disappear again.

This issue only occurs in Firefox on Windows (OS seems to not have an effect). When rending the content of the iFrame alone in a tab (not rendered in an iFrame) the issue does not occur.

In testing I was unable to reproduce this issue in a simple HTML page, and seems to be caused by a "perfect storm" of HTML structure and CSS layout. Unfortunately the page in which issue occurs is unwieldy. I have created a zip file which contains a ripped HTML state of the issue with all of the HTML and CSS files needed to reproduce the issue. There will be a few 404 errors on images, but that is unimportant. Apologies for not being able to reduce this issue to a small subset of functionality. I tried my best to find the specific combination of selectors which caused this issue but was unable to do so.


Expected results:

The glyph should render.

Comment 1

[Mats Palmgren (inactive)]

Attachment: OpenSans-Regular-webfont.woff

Comment 2

[Mats Palmgren (inactive)]

Attachment: testcase

Comment 3

[Mats Palmgren (inactive)]

I can reproduce the problem in Nightly 47 on Win7.
The bug does NOT occur in Nightly / 45.0.1 on Linux.