It would be nice to have the option to prevent new windows from grabbing the
focus if you're typing, scrolling etc in the current window. I'm not sure how
other window managers do it, but kwm's recent versions have various levels of
the strength of this option.
*** Bug 644 has been marked as a duplicate of this bug. ***
From xfwm4 documentation:
Some hidden options allow you to customize xfwm4 behaviour. They have to be
added by hand to your HOME/.config/xfce4/xfwm4/xfwm4rc file. You may have to
create this file.
Add this line to your xfwm4rc file to prevent windows from stealing focus.
Please note that this option is disabled by default because many apps don't
update their "NET_WM_USER_TIME" field very well IMHO.
*** Bug 717 has been marked as a duplicate of this bug. ***