Dear Maintainer,

to reproduce
1) when you have a card already presented to you, click on the edit button
2) add something to one of the fields such as the meaning field, [for
example some latex that
would require testing to make sure it renders correctly, or 'hello world']
3) click on 'preview' button

it displays a preview window

4) click on OK

what should happen
user should be popped back to the edit window

what does happen
user is popped back to the main mnemosyne window, as if one too many
windows closes
and any edits made are lost