Package: xfce4-panel Version: 4.12.0-4 --- Please enter the report below this line. ---
I find the same problem in current debian testing. The message is slightly different but equivalent: ** (gdmflexiserver:2770): WARNING **: Unable to create transient display: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.DisplayManager was not provided by any .service files --- System information. --- Architecture: amd64 Kernel: Linux 4.7.0-1-amd64 Debian Release: stretch/sid 500 testing ftp.de.debian.org --- Package information. --- Depends (Version) | Installed ====================================-+- ============= libatk1.0-0 (>= 1.12.4) | 2.22.0-1 libc6 (>= 2.4) | 2.24-3 libcairo2 (>= 1.2.4) | 1.14.6-1+b1 libdbus-1-3 (>= 1.9.14) | 1.10.10-1 libdbus-glib-1-2 (>= 0.88) | 0.108-1 libexo-1-0 (>= 0.5.0) | 0.10.7-1 libfontconfig1 (>= 2.11) | 2.11.0-6.7 libfreetype6 (>= 2.2.1) | 2.6.3-3+b1 libgarcon-1-0 (>= 0.3.0) | 0.4.0-2 libgdk-pixbuf2.0-0 (>= 2.22.0) | 2.36.0-1 libglib2.0-0 (>= 2.41.1) | 2.50.0-1 libgtk2.0-0 (>= 2.24.0) | 2.24.31-1 libice6 (>= 1:1.0.0) | 2:1.0.9-1+b1 libpango-1.0-0 (>= 1.14.0) | 1.40.3-2 libpangocairo-1.0-0 (>= 1.14.0) | 1.40.3-2 libpangoft2-1.0-0 (>= 1.14.0) | 1.40.3-2 libsm6 | 2:1.2.2-1+b1 libwnck22 (>= 2.30.7) | 2.30.7-5 libx11-6 | 2:1.6.3-1 libxext6 | 2:1.3.3-1 libxfce4ui-1-0 (>= 4.9.1) | 4.12.1-2 libxfce4util7 (>= 4.9.0) | 4.12.1-2 libxfconf-0-2 (>= 4.6.0) | 4.12.0-3 exo-utils | 0.10.7-1 Package's Recommends field is empty. Package's Suggests field is empty.