I have to admit: this is incredibly nit-picky of me, but it absolutely bothers me every time I open LTSpice that I find a gray background! I know, I know, you can very simply change the color preferences. And yes, it does last between sessions. However, I spend my time between three different operating systems: Windows 7, Ubuntu, and Xubuntu (for now). I install LTSpice under wine and it works great. But if its a re-install or I update the version, I am pulled back to those ugly default colors. So I decided to find the configuration file for LTSpice so I can set my colors once and keep it that way. Forever.