Uncomplete multiline PS1 after 'display-shell-version'

[Arnaud Gaillard]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: cygwin
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash.exe' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='cygwin' -DCONF_MACHTYPE='x86_64-unknown-cygwin'
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale'
-DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -DRECYCLES_PIDS   -I.
-I/usr/src/bash-4.4.12-3.x86_64/src/bash-4.4
-I/usr/src/bash-4.4.12-3.x86_64/src/bash-4.4/include
-I/usr/src/bash-4.4.12-3.x86_64/src/bash-4.4/lib  -DWORDEXP_OPTION
-ggdb -O2 -pipe -Wimplicit-function-declaration
-fdebug-prefix-map=/usr/src/bash-4.4.12-3.x86_64/build=/usr/src/debug/bash-4.4.12-3
-fdebug-prefix-map=/usr/src/bash-4.4.12-3.x86_64/src/bash-4.4=/usr/src/debug/bash-4.4.12-3
-Wno-parentheses -Wno-format-security
uname output: CYGWIN_NT-6.1 MD1MB4SC 2.8.0(0.309/5/3) 2017-04-01 20:47
x86_64 Cygwin
Machine Type: x86_64-unknown-cygwin

Bash Version: 4.4
Patch Level: 12
Release Status: release

Description:
        When using a multi-line PS1, pressing C-x C-v (invoking
*display-shell-version*) only redraws the last ("most bottom") line of the
PROMPT.


Repeat-By:
        ~$ PS1='a\nb\nc\nd$ '
        a
        b
        c
        d$ <C-x> <C-v>
        GNU bash, version 4.4.12(3)-release (x86_64-unknown-cygwin)
        d$


This was also tested on 4.3 and the bug occurred as well.

Best regards,

-- 
Arnaud Gaillard
El Magnifico