Force GNU screen to reflow to current terminal width on reattach

Depends how things are set up, but by default, something like this should work.

settitle() {
    printf "\033k$1\033\\"
}

Then run:

settitle NEWTITLE.

See screen title docs and GNU screen faq for more details.

Given Ctrl+A A is only changing it until the next command, it's probably being set by $PS1 (all shells), or $PROMPT_COMMAND/DEBUG trap (bash only) or precmd/preexec (zsh only).

You should look for any place that \e or \033 appears with k or \\ after it, basically like my settitle example above.

UPDATE

You said you had a custom preexec.

Why not change it to this:

if [[ "$TERM" == "screen" ]]; then
   local CMD=${1[(wr)^(*=*|sudo|-*)]}
   echo -n "\ek${TITLE:-$CMD}\e\\"
fi

Then you can set a custom title by running:

TITLE="my title"

and unset the title by running

TITLE=

Don't forget to change precmd and $PS1 as well if necessary.

ASIDE

You could even extend this to all terminals (e.g. xterm, gnome-terminal, etc.) by not hard coding the \ek and \e\\.

This is how I do it:

terminit()
{
    # determine the window title escape sequences
    case "$TERM" in
    aixterm|dtterm|putty|rxvt|xterm*)
        titlestart='\033]0;'
        titlefinish='\007'
        ;;
    cygwin)
        titlestart='\033];'
        titlefinish='\007'
        ;;
    konsole)
        titlestart='\033]30;'
        titlefinish='\007'
        ;;
    screen*)
        # status line
        #titlestart='\033_'
        #titlefinish='\033\'
        # window title
        titlestart='\033k'
        titlefinish='\033\'
        ;;
    *)
        if type tput >/dev/null 2>&1
        then
            if tput longname >/dev/null 2>&1
            then
                titlestart="$(tput tsl)"
                titlefinish="$(tput fsl)"
            fi
        else
            titlestart=''
            titlefinish=''
        fi
        ;;
    esac
}


# or put it inside a case $- in *i* guard
if test -t 0; then
    terminit
fi

# set the xterm/screen/etc. title
settitle()
{
    test -z "${titlestart}" && return 0

    printf "${titlestart}$*${titlefinish}"
}

Then you can change your preexec to:

if [[ "$TERM" == "screen" ]]; then
   local CMD=${1[(wr)^(*=*|sudo|-*)]}
   settitle "${TITLE:-$CMD}"
fi

Not sure if I had the same issue as you, but sometimes I've the similar screen behaviour every time I network was accidentaly disconnected.

After a while ( about 10-15 minutes ) screen is available again for reconnection. After some invetigations, I've found a small note in the man page:

   nonblock [on|off|numsecs]

   Tell  screen  how to deal with user interfaces (displays) that cease to
   accept output. This can happen if a user presses ^S or a TCP/modem con‐
   nection gets cut but no hangup is received. If nonblock is off (this is
   the default) screen waits until the display restarts to accept the out‐
   put.  If  nonblock is on, screen waits until the timeout is reached (on
   is treated as 1s). If the display  still  doesn't  receive  characters,
   screen will consider it "blocked" and stop sending characters to it. If
   at some time it restarts to accept characters, screen will unblock  the
   display and redisplay the updated window contents.

May be it'll help somebody, cause this is the only page about screen freezes after disconnetion google gave me.