Affected versions

• 78.0.1, 79.0b9, 80.0a1 (2020-07-16); 80.0b1;

Affected platforms

• macOS 10.13.6;

Steps to reproduce

1. Launch Firefox, access any article ex: link;
2. Scroll down in page and Enable Screen reader mode;
3. Click on the Type Controls button from the Reader Controls section;
4. Tab-select the <- -> option;
5. Hover over the above and bellow options (+ =);

Expected result

• hover effects do not cause issues;

Actual result

• while hovering over top/bottom adjacent options overlaps the blue selector;
• in some cases the effect persisted even as hovering away from the buttons;

Regression range

• not a regression, visible with new design of reader tool;

Additional notes

• attached recording with the issue;
• suggested severity is S4 due to the uncommon nature of the issue.

This is a graphics rendering artifact and not a bug in reader mode.

Can we get an about:support for the affected machine?