I'm using irssi in one pane and nicklist.pl in the other, and whenever I'm in the irssi pane, the nicklist pane is dimmed:
How do I stop the inactive pane from dimming?
On newer versions of iTerm2 (Build 3.3.2+ for me), unchecking the following setting solved this:
Preferences(⌘,) -> Appearance -> Dimming
Then uncheck the first option:
"Dim inactive split panes"