I’m slowly but surely building up my config file to be just like I like it. However, I’ve noticed that from using KDE for so long, that my fingers are trained to use the
Alt+Left
combination to make my browers go back one page (same thing as clicking on the back button).
I don’t know why you think this is controlled by FVWM; it isn’t. The application would have to respond to that series of key presses to decide whether or not is able to do anything about it.