URL:
  <https://savannah.gnu.org/bugs/?68516>

                 Summary: screen display corruption with some special
characters
                   Group: GNU Screen
               Submitter: vinc17
               Submitted: Mon 13 Jul 2026 07:55:09 AM UTC
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Unlocked
                 Release: 5.0.1
           Fixed Release: None
         Planned Release: None
           Work Required: None


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Follow-up Comments:


-------------------------------------------------------
Date: Mon 13 Jul 2026 07:55:09 AM UTC By: Vincent Lefèvre <vinc17>
With GNU Screen v4 and v5 (tested with 4.9.1 and 5.0.1 in Debian/unstable and
with 5.0.2 in Termux/Android):

screen sh -c "echo
'MQpSZW1pbmRlcjogWQhZ4oGgbwhv4oCLCG/igIvigaF1IGjigaQI4oGk4oGhYXYIduKBomUIZeKBoCBhCGHigaAgbghu4oCMCG7igIzigaFlCGXigaJ3CHfigI0Id+KAjeKBoyBtCG3igaIIbeKBouKAi2UIZeKBoghl4oGi4oCLcwhz4oGjCHPigaPigIxzCHPigI1hCGHigIsIYeKAi+KAjGcIZ+KAjWUIZeKBoCEKZm9vCg=='
| base64 -d; sleep 9999"

to be tested with different terminal widths. Also do tests by reducing the
initial width. See below.

Note: the second line of this testcase ("Reminder: You have a new message!"
with various special characters in it was the subject of a spam I received,
and with Mutt running in Screen, the line that followed got also corrupt with
any terminal width).

With 80 columns:

1
Reminder: You ave a new message!
foo


(which is correct: same behavior as without GNU Screen).

When it is reduced to 79 columns:

1
Reminder: Yoou have a nneww mmeesssaage!
foo


With 63 columns:

1
Reminder: You ave a new message!
                               foo


So as one can see, this bug can affect the line that follows.

With 62 columns:

1
Reminder: You ave a new message                              e
!
foo


With 61 columns:

1
Reminder: You ave a new message!

foo


Note the blank line before "foo" in the case just above.

See also the attached "mbox" file. With my Mutt configuration (using "set
arrow_cursor"), I get with Mutt in GNU Screen in a 80-column terminal:

                                                              2 N   2026-07-12
a
@b.invalid     (   0) foo

instead of

->    1 N   2026-07-12 [email protected]     (   0) Reminder: You have a new
message!
      2 N   2026-07-12 [email protected]     (   0) foo








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