Reproducible with 44.0RC (Build ID: 20160118143821), latest Aurora 45.0a2 and Nightly 46.0a1 (from 2016-01-18) Affected platforms: Windows 7 x64, Windows 10 x86, Mac OS X 10.9.5 and Ubuntu 14.04 x86 Steps to reproduce: 1. Launch Firefox and go to about:preferences#search 2. Randomly delete One-click search engines Expected result: No flicker. Actual result: Flicker in Default Search Engine drop-down. Additional notes: 1. Also reproducible with 40.0RC - not a recent regression.
Also reproducible with Nightly 38.0a1 2015-02-01 - not a regression.
put pretty low as it's such an edge case and it's lower than our other quality work. we'd gladly take a patch from a contributor