Hi everyone, I am using ArchLinux and dwm 6.0 for a long time. Today I notice that dwm-6.1/BUGS, with report from voltaic, I also have 2 monitors with different resolution (at home and my office), I wrote a script helps me autoextend VGA output (with exactly resolution of the current extended-monitor). Repo in here: https://github.com/88d52bdba0366127fffca9dfa93895/txrandr , hope this helps you.
Ref: http://lists.suckless.org/dev/1004/3788.html I know this thread is very old and I'm so sorry for any annoyance. Have a good day, guys.