URL: https://fr.sports.yahoo.com/video/le-nouveau-dessin-faro-la-080000196.html
Browser / Version: Firefox Mobile Nightly 55.0a1 (2017-05-01)
Operating System: Nexus 5 (Android 6.0.1) - Resolution 1080 x 1920 pixels (~445 ppi pixel density)
Problem type: Something else - I'll add details below

Prerequisites

1. Account created and signed in.

Steps to Reproduce

1. Navigate to: https://fr.sports.yahoo.com/video/le-nouveau-dessin-faro-la-080000196.html.
2. Type in a comment.
3. Observe “Publier” (“Post”) button.

Expected Behavior:
The button becomes active (e.g. blue color.)

Actual Behavior:
The button remains inactive (e.g. gray color.)

Note:

1. Reproducible on Firefox 52.0 Release
2. Not reproducible on Chrome (Mobile) 57.0.2987.132.
3. Also reproducible on US site (https://sports.yahoo.com/news/lawyer-raiders-pick-gareon-conley-now-says-accuser-consensual-sex-223954315.html).
4. This is an UI issues, considering that the "Post" button is functional (after being tapped the comment is saved).
5. Screenshot attached.

Watchers:
@softvision-sergiulogigan
@softvision-oana-arbuzov

sv; country: fr

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