I have a pretty hacky workaround for this. It seems to be working fine initially, but I'm guessing this will break something eventually. BACK UP YOUR PROFILE BEFORE TRYING THIS
cd ~/.mozilla/firefox
mkdir screen1
mkdir screen2
# for bash
shopt -s dotglob
# for zsh
setopt GLOB_DOTS
cd screen1
ln -s ../<YOUR PROFILE>/* .
rm .parentlock
cd ../screen2
ln -s ../<YOUR PROFILE>/* .
rm .parentlock
From a terminal on screen 1...
firefox -P screen1 -new-instance
From a terminal on screen 2...
firefox -P screen2 -new-instance
I have a pretty hacky workaround for this. It seems to be working fine initially, but I'm guessing this will break something eventually. BACK UP YOUR PROFILE BEFORE TRYING THIS
cd ~/.mozilla/firefox
mkdir screen1
mkdir screen2
# for bash
shopt -s dotglob
# for zsh
setopt GLOB_DOTS
cd screen1
ln -s ../<YOUR PROFILE>/* .
rm .parentlock
cd ../screen2
ln -s ../<YOUR PROFILE>/* .
rm .parentlock
From a terminal on screen 1...
firefox -P screen1 -new-instance
From a terminal on screen 2...
firefox -P screen2 -new-instance
Again, USE WITH CAUTION AND MAKE BACKUPS FIRST