If this is a valid issue, then I can send a PR for the same.

Why would you need to set a tabindex. When not included, the code source order is the default tabbing order of a document, with links, form controls and objects getting focus as they appear in the source code.

Clearly you don't work with my clients who have asked us to make the tab key skip over "non relevant" fields, even against all advice.

If that is the only use case for adding this then i would definitely not be in favour of adding the ability to break accessibility to the core of joomla

There are 2 ways to argue it.

1. The tabindex attribute is part of the HTML spec and should be supported in core.
2. You argue that its use breaks accessibility on sites and shouldn't be supported, in which case we should explicitly not support (and remove from core) anything that can create accessibility problems.

@mbabker

1. There are lots of things in the HTML spec that we dont expose in the UI and nor should we
2. Absolutely and if they are identified then we can work to remove them

I am closing this for the reasons stated above