Version: 61.0a1 Build ID: 20180327120140 Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:61.0) Gecko/20100101 Firefox/61.0 Affected: macOS 10.12 & Ubuntu 16.04 Steps: 1. Open browser 2. Open Devtools go to Accessibility tab 3. Observe the Enable Accessibility Features button Expected result: Enable Accessibility Features button should be visible on all instances as a grayed background button in a dark grey frame. The button should be displayed as example in case of the Memory tab, Take snapshot button. Actual result: Only the grey background of the button is visible without a dark grey frame, if the macOS contrast settings are set to normal. If the contrast settings are higher than normal even the grey background becomes invisible and as no frame is added to the button one can't tell if it's just a text displayed or a button.

This is fixed on what has landed on nightly.

Verified fixed on Mac OS X 10.12 and Ubuntu 16.04 x64 using the latest Nightly 61.0a1 (2018-04-25).