Input of the admin password impossible

[CAUDOUX DIDIER]

Command :
gksu /opt/lampp/manager-linux-x64.run
Message :
/usr/share/themes/Ambiance/gtk-2.0/apps/mate-panel.rc:30: error: invalid string constant "murrine-scrollbar", expected valid string constant
GNOME_SUDO_PASS
sudo: 1 saisie de mot de passe incorrecte

In the window that opens to enter the admin password, it is not possible to access to the password field. It is only possible to click on the buttons "cancel" or "validate".

See screen-shot in file attached.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: gksu 2.0.2-9ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 31 23:52:38 2017
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-01-14 (290 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
SourcePackage: gksu
UpgradeStatus: Upgraded to artful on 2017-10-21 (10 days ago)