I have been using a double-click action on the mouse for well over twenty years (Amiga, Mac, Wintendo, SunOS, Linux (KDE and Gnome).
Knoppix seems to want a single-click to open files and icons in the LXDE file manager.
I googled and tried to find the setting in preferences but cannot. I did see this very old thread - http://knoppix.net/forum/threads/457...on-desktop-etc. - but the solution doesn't seem to be relevant any more.
Any help?