Hi Carl Sorry about that, we overlooked the print function but I've added a fix to the incemail.php script in the updater and if you get a new copy it should solve this problem.
I tested this earlier and it was fine for me - can you force a refresh (Ctrl+Refresh) on the page in case the css has been cached and isn't showing for that reason?
It seems to be a glitch in Chrome, Firefox is fine.. If after clicking the print invoice button.. you "cancel" the automatic printer opener when it opens.. It will show the invoice.. then you can right click and print.
So the automatic printer opening is interfering in some way.. ah well..