Answer the following question: Extract the answer to the question from the following context. Question: What made the new user interfact more confusing and difficult to learn? Context: Windows 8 was released to a mixed critical reception. Although reaction towards its performance improvements, security enhancements, and improved support for touchscreen devices was positive, the new user interface of the operating system was widely criticized for being potentially confusing and difficult to learn (especially when used with a keyboard and mouse instead of a touchscreen). Despite these shortcomings, 60 million Windows 8 licenses have been sold through January 2013, a number which included both upgrades and sales to OEMs for new PCs.
Answer:
when used with a keyboard and mouse