[a11y]: Modal interaction problems

[mbgower]

Description

This issue covers what I would consider 'bugs' in the modal components. It is complementary to the discussion #12726 I have opened, and contains information based on the Modal component review for accessibiliity. It is complementary to a review of Carbon website guidance carbon-design-system/carbon-website#3312.

Items to address

Beta Give feedback

1. [a11y]: Modal: Most of the modals are not properly dismissable in storybook #13710
   component: modal role: dev 🤖 severity: 2 type: a11y ♿ type: bug 🐛 +5
   
2. [a11y]: Modal: A keyboard user cannot activate the scrollbars on a dialog #13711
   component: modal role: dev 🤖 severity: 3 type: a11y ♿ type: bug 🐛 +5
   
3. [a11y]: Modal: doesn't return focus properly on dismissal #13680
   component: modal role: dev 🤖 severity: 2 status: waiting for author's response 💬 type: a11y ♿ type: bug 🐛 +6
   
4. [a11y]: Modal: The 'fade' effect on dialogs with overflow body text creates some odd behaviours #13714
   component: modal role: dev 🤖 severity: 2 type: a11y ♿ type: bug 🐛 +5
   

Reproduction/example

https://react.carbondesignsystem.com/?path=/story/components-modal--with-state-manager

[mbgower]

I just encountered a 'modal' dialog in Workday. Obviously not a Carbon component, but a real-life situation helps discuss. (Note that View Details did not have focus when this appeared. That was a result of me tabbing.)

My keyboard was constrained to tabbing between the X button to close and the link to "View details". Even though there was no decision needed on my part, I was forced to intentionally dismiss via keyboard.
However, with a mouse, I could simply click anywhere and the 'modal' disappeared.
In such a situation, it would be easy for the user to not even see the message before dismissing. For a dialog that required interaction, that would be a poor user experience. In this situation (where a response wasn't really needed) the impact is neglibile.
So, should it BE a modal?
And if it isn't a modal, should tabbing away from it dismiss it? Is there any dropback to that interaction?

[mbgower]

I added issues 7 and 8

[mbgower]

@sstrubberg , IMO the items marked as Sev 2 remain appropriate for higher priority (issues 1, 2, 5 and 7.2)