Tab select triggered when tabbing in child form

[bmayen]

I have a tab which contains a modal which contains a form. If I open its child modal and attempt to tab through the form, the tab select event fires.

This is particularly problematic in my case because I refresh the tab's data when it is selected; which causes the child form to close.

[bmayen]

Workaround: $event.heading is undefined when select is fired this way. When selected directly, heading is defined as expected. So I'm able to ignore the event in the case that heading is undefined.