Business theme seems to be affecting Facebook comment formatting using "Facebook Wall" module

I have Facebook Wall installed on my site. With Business as the default theme, comments on FB wall posts displayed using the module have a fixed (and very tall) height - see this screenshot. This doesn't happen in other themes - see this screenshot for the same wall in Bartik, where the comments wrapper resizes as necessary.

There is a CSS class in the Facebook Wall CSS called .comment which I thought could be clashing with the .comment class in Business for normal Drupal comments, but modifying or removing the latter doesn't make any difference to the Facebook Wall comments style. In case it helps, the full default CSS file for Facebook Wall is here.

I realise Facebook Wall isn't as widely used as Business but any tips would be appreciated :)