Using Control-C as Ivan suggested works if you don't need the clip and until you write something on the second worksheet. The post-it solution is better :-)
But it still does not solve another problem: when focus is lost, the status bar with average, count and sum is lost. It is an issue because I also use several worsheets and I need to see those values. Of course I could add a formula to some cell but not if the worksheet is protected...