Sibelius 7.5 doesn't use the Windows convention of allowing to use the Enter key in a print dialog to begin printing. In Sibelius 7.5, you have to click on the Print button to start printing instead. It might not seem to be such a big problem, but it's pretty annoying to me. I don't see a reason why Sibelius can't behave as other Windows applications do. Sibelius 5 allowed you to begin printing with the Enter key, by the way.
Idea No. 579