Behaviour setting on configure desktop

There is a problem (bug) with the settings for icons, in that I cannot set them. On my own computer they simply don't display, no matter how many settings I tick in the behaviour setting. I rarely use icons so this is a very minor problem. But I am setting up an installation for a client who relies on icons. He will be most upset to have the wrong ones. I go through ticking and unticking the boxes for the various hardware and files, click on "apply", and nothing changes, except that all the settings return to the default. The icons I want to get rid of remain and the ones that I want to show remain stubbornly invisible. Has anyone any suggestions for what I can do about this? Lisi