Calendar Create event modal : Focus moves inappropitely for the modal

Issue Summary

In the Create event modal, when the user navigates into the modal the focus moves out of the modal.

Tested URL

https://instenv-19177-d2sp.instenv.internal.atlassian.com/display/TEST/calendar/ea467a88-11b8-4c6d-93d9-24c8444ea87a?calendarName=test%20cnd 

Screen Recording

Focus moves out of the modal.mov

Steps to Reproduce

1. Launch the URL
2. Navigate to the main content area where the calendar for the space is present.
3. Navigate into the calendar section and activate on any date to open the Create event modal.
4. Keeping the screen reader on, navigate into the form input fields.

Actual Results

The Modal dialog containing the information to Create an event, when the user navigates through the modal the focus moves out of the modal. When the modal dialog is displayed on the screen, the keyboard focus moves to the background content. This makes the keyboard user as well as assistive technology user unaware of the scope of the modal.

Expected Results

Ensure that the keyboard focus moves at the beginning of the modal dialog content when the modal dialog gets displayed on the screen.

The focus should not go to the background content when the modal is active.

This will make the user aware of the content and able to use the function with the keyboard.

Workaround

Currently, there is no known workaround for this behaviour. A workaround will be added here when available