Allin Cottrell a écrit : I agree with Sven! Anyway, the close button on the toolbar seems to do things quite well. Why not to abolish the big button on the bottom? Otherwise, there are two small bugs in the "Tools" menu. 1. On the "Test calculator" window, when you check the "Assume std dev ..." option and click Ok a pop-up appears saying "Bad PNG header: Got bytes e0 22 0" and it doesn't produce the distribution graph. 2. On the "Statistical tables" window, try to introduce 0.2 as the right-tail probability for the normal distribution. As I'm using the french version the point obviously doesn't work and I changed it by the comma "," and that's fine. But, when I choose the distribution graph menu for the normal distribution N(0,1) I got the same error message "Extraneous character '.' in data"??? Artur