Search - Popout : Dialog is missing appropriate role and attributes

Issue Summary

The "Search" dialog which appears when user activates "Search" field present in header region is missing ARIA roles/attributes

Tested URL

https://instenv-10949-s8ch.instenv.internal.atlassian.com/display/TES/test12+Home 

Steps to Reproduce

1. Launch URL https://instenv-10949-s8ch.instenv.internal.atlassian.com/display/TES/test12+Home 
2. Navigate to "Search" field present in header region and activate it with Tab/Space bar key.

Actual Results

When user activates "Search" field , "Search" modal dialog appears on a page which is not announce by screen reader. Inshort screen reader users are unaware that modal dialog appears on page and it will be confusing experience for screen reader users.

Expected Results

Screen reader should render when "Search" modal dialog appears on screen. For this provide role="dialog", set aria-modal="true"and add "aria-labelledby" attribute to the <div> element containing the modal dialog content.

Screenshot

Workaround

workaround

Bug Ref: 724462