The Kendo UI Toolbar widget supports navigating between toolbar items using the TAB key if the navigateOnTab option is set to true. However, if the page is resized after the widget's creation so that more items are visible (i.e. not overflown) than before, those items are not reachable via keyboard.
This DOJO demonstrates this behavior: When the toolbar is created, the container is only 300px wide, which offers room for the first three items only. When setting the width back to "auto" afterwars, the rest of the items moves back out of the overflow menu, but cannot be focused.
Calling resize() does not help.