Bug#923051: screen doesn't clear the screen for certain UTF8 characters

[Bruce Momjian,,,]

Package: screen
Version: 4.5.0-6
Severity: normal
Tags: l10n

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?

Jessie did not display emoji UTF8 characters properly in the mutt built-in 
pager, so I retested with Jessie.

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

I emailed myself three lines of text: one containing ASCII, one Latin-1 UTF8, 
and one emoji UTF8.
I then viewed the email with the mutt built-in pager.

   * What was the outcome of this action?

The end of the emoji UTF8 line displayed text that appeared on that line before 
built-in mutt viewer started, meaning the line was not cleared from its previous
contents.

Here is the actual display:

        abc
        ä·öÈ
        😳😜😅                                     ian                             
       oup
                                                ---                             
       ---

The "ian" and "oup" are from the previous mutt display screen listing all my 
emails in the mailbox, and are not part of the email.  Using Control-L makes 
them properly
disappear.  Doing this test without 'screen' allowed for proper display.

I tested this in Gnome terminal and putty, so I don't think it is the terminal 
emulator.  It might be caused by mutt, but mutt only shows the error when it is 
run as
part of screen.  I tested this with screen default, no screenrc file.  I am not 
sure how to test this further but am open to suggestions.

   * What outcome did you expect instead?

I expected no text from the previous mutt screen to appear.

*** End of the template - remove these template lines ***


-- System Information:
Debian Release: 9.8
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.9.0-8-amd64 (SMP w/16 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), 
LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages screen depends on:
ii  libc6      2.24-11+deb9u4
ii  libpam0g   1.1.8-3.6
ii  libtinfo5  6.0+20161126-1+deb9u2

screen recommends no packages.

Versions of packages screen suggests:
pn  byobu | screenie | iselect  <none>
ii  ncurses-term                6.0+20161126-1+deb9u2

-- Configuration Files:
/etc/screenrc changed [not included]

-- no debconf information