Tab navigation is not working inside OutlookBar.
DECLINED: Duplicated with https://feedback.telerik.com/Project/143/Feedback/Details/113083-outlookbar-tab-navigation-is-not-working
Yes it is - see the item description for a link to the bug, where you can add comments and follow its progress. This item is declined due to duplicity.
If this is still a known bug, it should be fixed. Otherwise, people is going to spent hours trying to figure out the workaround.