Accessibility Issue: Dialogs should trap focus

[harinair]

When a dialog is drawn with multiple elements, keyboard navigation allows the user to switch focus. But when the last element is focused and the tab key is hit, the focus should switch back to the first element. This is reported as fixed in #4384 but still repro'd in 0.20.

• I have searched the issues of this repository and believe that this is not a duplicate.

Steps to Reproduce (for bugs)

Create a dialog with a few fields. Use tab to switch focus to the last element. Hit tab once again. Check which element has the focus. Accessible dialogs should switch focus to the first element inside the dialog.

Context

This is an accessibility issue. Reproducible in Material UI demo page. Here is how Material UI behaves:
http://www.material-ui.com/#/components/dialog
Open a dialog and try tabbing. It tabs through all the fields in the page.

This is the expected behavior from a dialog that is accessible:
https://material.angular.io/components/dialog/overview
Open a dialog and try tabbing. It tabs through only the fields in the dialog.

Tech	Version
Material-UI	0.20.0

[oliviertassinari]

@harinair You are 💯 right. This behavior is present in the v1-beta branch. Just don't use the v0.20 branch for anything serious.

[ryanmitts]

This still happens, should I create a new issue to have this re-opened?

[oliviertassinari]

@ryanmitts You can open a new issue if you have a live minimalistic reproduction :).