How to reproduce:

1. Click Share
2. Add a bunch of people
3. Share the page
4. Realise you forgot one person
5. Click Share again
6. See the list of people you've already shared with
7. Add the latest person
8. Click Share

What happens:

Everyone you first shared it with gets two emails

I realised if I click 'Cancel' on the dialog then the people are "cleared" and I won't be sharing with the same people twice. Shouldn't this behaviour be standard when the inline dialog is closed?