I agree with Steven, John and Deborah,
It is not a big minus, it is a big plus. This topic comes up from time to time and I have never understood the fascination of opening more than one chart at a time. It literally takes less than 0.3 seconds to hit CTRL + S. Open the other patient's chart, see him or her, send him or her on his or her way (gotta love good English), and then open the other chart.
If you really need to have more than one chart open, then get a lot of memory and install VM on your PCs. Then you can run 2, 3 or 10 Amazing Chart programs at a time.
