Thanks for this series of discussions - having learnt programming in my youth when FORTRAN was the thing to learn, the cooments are interesting. ON single or double clicks, it is a more general point that there is not enough consistency between things that sometimes a single click is required, sometimes a double. And if there is no immediate visible response you think that the double click has not worked and so you click again. This is a problem on my windows xp computer where the slightest movement or wrong timing on a double click and it interprets it as only single click and so does not open something from desktop. Another problem on my Ubuntu computer. I can't use BBC iPlayer (through Firefox) because it does not recognise the flash player which I have installed more than once. The iplayer screen gives me an error message saying that I need to install flash, and a link to macromedia. But following this and installing flash palyer still does not cure the problem. So no iplayer. (iPlayer is a poor app. anyway, very unfit for purpose, but unavoidable.) Thanks Robert Ubuntu user On 21 February 2011 22:36, JIm