@dunhill - I don't have a Mac to try it on. One suggestion it might be - do you have some super long identifiers in your books? Perhaps that ISBN dropdown is being forced very wide by the contents? You could try dropping it down to see if you can spot the long entry/entries, and/or try viewing in the tag browser.
Nothing should have changed in this release regarding the dialog sizing.
EDIT: I've managed to replicate the same issue myself, that is what your problem is being caused by. I will see if I can constrain that combobox width to a maximum in Qt somehow...
