STR: (Win7_64, Nightly 43, 32bit, ID 20150913030204, new profile, safe mode) 1. Set layout.css.devPixelsPerPx -> 1.25 OR set layout.css.devPixelsPerPx -> -1.0 (default) and set font size = 125% on your OS Result: Locationbar (23.8px) has greater height than the searchbar (23.6px) Expectations: They should have the same width - 24px, just like when I set layout.css.devPixelsPerPx -> 1.0 (100%) Note: You can see on attached screenshot that location bar has visually greater height (by 1px) Here are screenshots of browser toolbox saying that location bar is 23.8px height and searchbar is 23.6px height > locationbar https://dl.dropboxusercontent.com/s/pg1g59ge5ngzvaf/toolbox%20location%20bar%20-%20Locationbar%20has%20greater%20height%20than%20the%20searchbar%20on%20HiDPI.png?dl=0 > searchbar https://dl.dropboxusercontent.com/s/9v2vp7lb501yc6f/toolbox%20searchbar%20-%20Locationbar%20has%20greater%20height%20than%20the%20searchbar%20on%20HiDPI.png?dl=0 Selectors: location bar (#urlbar-wrapper) searchbar (#searchbar)

... They should both have the same height == 24px. This was regressed between 2015-04-09 and 2015-04-10. I think it's bug 1147702 > pushlog_url: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=d34160cac9cd4c29e6b1a85b5857885ae9f993c6&tochange=07839dbde05cebef84f067640015d7c055ddb6c4 But the main issue of HiDPI theme is bug 477157 which breaks literally everything that involves borders

I believe this is fixed. Let me know if you still see this.

>>> My Info: Win7_64, Nightly 51, 32bit, ID 20160913030425 (2016-09-13) I see this.