Dear Maintainer,

I have a program which runs in one window of my screen, monitoring certain parameters.
When those parameters reach certain values, it executes a command in another program, running in
another window of the same screen.

So if the windows are 1 and 2, then the program in screen 1 will execute a command
screen -p 2 -X stuff "some commands". Program in window 2 receives those commands as if
they came from the keyboard. Very nice.

This worked for several years, no problems.

However, recently (days ago), this started failing: now whenever I run screen -p (number),
I get an error saying "could not find pre-select window".

Note: I have only one screen process running. This does not seem to be about the command being
sent to the wrong screen session.

Restarting screen did not bring any change.