Sorry for leaving the title blank in the previous post. I have to add a couple of details. When I launch firefox the first time, it looks like this:
http://jesgue.homelinux.org/temp/fvwm-firefox.png If I close it and re-open it again, it looks like this: http://jesgue.homelinux.org/temp/fvwm-firefox2.png If I maximize that window then it looks like normal, but it exhibits the behavior I explain on the previous mail. -- Jesús Guerrero