Focus issues on IE

Showing the tooltip on focus is causing problems in IE since, after clicking an element (such as a div), it seems to retain focus until one clicks elsewhere and therefore the tooltip does not disappear until that is done.

I'm thinking about what is the best way to solve this. Is the tooltip only being shown on focus because of input fields? If so, perhaps the best would be to add the :focus selector only to those fields. If this seems good, I can make a pull request.

Start by reproducing the tooltip behavior in Internet Explorer after clicking a non-input element, then inspect the tooltip's focus-state styling and its use of the :focus selector. Done means tooltips no longer remain visible on focused non-input elements while focus behavior for relevant input fields is preserved.

Written by the indexing model from the issue text.