Issue Summary:

When using router.open with a mailto: link, it opens a blank page in a new tab instead of launching the user's default email client. This issue is reproducible in a dashboard gadget with the following code:
{{}}

<Button  text="Email support (router.open)"  onClick={() => router.open('mailto:email@email.com')} />

{{}}

Steps to Reproduce

1. Add a button to a dashboard gadget that calls router.open('someone@example.com') on click.

1. Click the button.

1. Observe that a new blank tab opens instead of the email client.

Expected Results

Clicking the button should open the user's default email client with a new message addressed to the specified email.

Actual Results

A new blank tab opens.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available.