I believe all current releases allow multiple pan sessions to be run at
once, but a reasonably recent change in git now tests for another running
pan instance and shuts down if it exists, as the simplest fix for a bug
involving accidentally starting a second instance using the same data
dir. That's a bit frustrating here, but I only do the text instance at
all regularly any more, so it hasn't bothered me as much as it would
someone regularly using multiple separate pan sessions, as I used to.
I've been going to investigate how it's doing that with a eye toward a
workaround (if it's a socket listener in $TMP as used for example with
claws-mail, setting $TMP just as I set the data dir var should work, just
as it does with claws-mail, which I run two instances of, one for mail,
one with the appropriate plugin as my feed reader). or filing a bug to
create a mechanism that can be worked around if I don't find any, but
I've not done so yet.