Bug 266393 – AX: The keyboard navigation is different when Full Keyboard Access is enabled in mac

• Status: NEW
• Component: Forms

What steps will reproduce the problem?
(1) Open the following JSFiddle example: https://jsfiddle.net/zp65h7j3 in Mac
(2) In Mac turn on the "Full Keyboard Access" under accessibility -> keyboard
(3) Try to native through the div using the keyboard

What is the expected result?
When we are navigating through the available content using `TAB` then the expected order is div 1 -> div 2 -> div 3 -> div 4 -> div 5 -> div 1 followed on 

What happens instead?
The order is not constant and keeps on changing  when Full keyboard access is enabled which is like a bug and makes it hard to handle the keyboard navigation in the custom components

[Radar WebKit Bug Importer]

<rdar://problem/119651246>