new UI still lets me select tabs

[tromey]

I love the new UI.

If I click on a tab, it turns bold. But in the new everything-always-visible scheme, it doesn't seem like clicking on a tab should do anything at all.

[fitzgen]

I'd like to re-add the keyboard navigation that used to exist before the React-ification for selecting individual bugs with either vim-style hjkl or arrows and then opening in a new tab with RET.

That would make the selected tab still have a meaning.

[fitzgen]

But yeah, clicking is pretty useless.