The close button of the preview issue view on the right side in the backlog, active sprint or kanban board does not receive focus and cannot be reached and operated by keyboard users.
Although it is possible to use the keyboard shortcut 't' to open/close the preview, it is not intuitive, non-experient Jira users tend to use <tab> to reach the objects.

Environment
MacOS/Chrome 92.0.4515.131/Firefox 90.0.1 (64-bits)
Windows/Firefox 90.0.2 (64-bits)/Chrome 92.0.4515.131

Steps to reproduce

• Open a board, for instance, using the keyboard shortcut 'g' + 'a';
• The page will be loaded with the focus at the "Active Sprints" or "Kanban Board";
• Press <tab> to reach the issues and hit <enter> to open the issue at the preview issue view;
• Press <tab> to reach the close button and close the preview.

Expected results

• it should be possible to reach the close button and hit <enter> to close the preview.

What is observed

• The close button does not receive focus.

Workaround

Use the Keyboard shortcut 't' to open/close the preview.