Steps to reproduce the issue

Go to Media Manager and try to use it with keyboard only

Problems detected

• It is impossible to navigate inside the folders tree (tabindex=-1)
• Poor / incomplete focus visibility on elements

Firefox

Chrome

• No focus visible at all in the grid
• Elements in the grid are not interactive, it is not possible to open a folder

• When / if you reached a folder or image on the grid, you can click with the arrow keys and get the functions visible. They don't dissapear if you tab further

• No focus on modals -> PR #36892

Expected result

The Media Manager should be accessible for all kind of users.

Actual result

It is not possible to use the Media Manager with keyboard only.

System information (as much as possible)

Joomla 4.1.1-dev
Windows PC
Firefox and Chrome (also screen reader extension tested)

Additional comments

https://levelaccess.com/creating-an-accessible-aria-tree-control
https://dequeuniversity.com/library/aria/tree-view
https://vuescript.com/best-tree-view/