URL: www.booking.com
Browser / Version: Firefox Mobile Nightly 55.0a1 (2017-05-24)
Operating System: LG G4 (Android 5.1) - 1440 x 2560 pixels (~538 ppi pixel density)
Problem type: Layout is messed up

Steps to Reproduce

1. Navigate to: www.booking.com and login with valid credentials.
2. Navigate to: https://secure.booking.com/mysettings.fr.html?aid=304142;label=gen173bo-1DCAEoggJCAlhYSDNYA2hNiAECmAENuAEJyAEP2AED6AEBkgIBeZgCAqgCAw;sid=b8db0adcb0b62b27fe84c6d2e4fff538
3. Observe the dropdown list arrow.

Expected Behavior:
The dropdown list arrow is correctly displayed.

Actual Behavior:
The dropdown list arrow is duplicated.

Notes:

1. The issue is not reproducible on Firefox 53.0 Release (Mobile).
2. The issue is not reproducible on Chrome (Mobile) 58.0.3029.83.
3. Screenshot attached.

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

sv; country: fr

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