Clicking "Add" on Add New Link Type asks for confirmation to leave this page

Under Issue Linking I defined values for a new link type and clicked on "Add".

The browser popped up a window that says "Confirm?"

Are you sure you want to navigate away from this page?
You made changes ... they'll be lost (etc.).

If you click on "Ok", the new link type is still created.

I've tried this several times – it continues to happen every time.