lxshortcut isn't in sid anymore, so the removal should be intentional
lxshortcut:
Installiert: (keine)
Installationskandidat: 0.1.2-3
Versionstabelle:
0.1.2-3 0
500 http://ftp.debian.org/debian/ unstable/main amd64
500 http://debian.siduction.org/ stable/main amd64 Packages
500 http://debian.siduction.org/ testing/main amd64 Packages
A hint may be the debian/control file for libfm
PackagesPackage: libfm-tools
Section: misc
Architecture: any
Depends:
${misc:Depends},
${shlibs:Depends}
Breaks:
libfm-gtk-bin (<< 1.1.1 )
Conflicts:
lxshortcut
Replaces:
libfm-gtk-bin (<< 1.1.1),
lxshortcut
Provides:
libfm-gtk-bin,
lxshortcut
Description: file management support (utilities)
LibFM provides file management functions built on top of Glib/GIO
giving a convenient higher-level API.
.
This package contains applications libfm-pref-apps and lxshortcut.
So the removal of lxshortcut has absolutely nothing to do with hibernation, user switching etc - this is systemd, especially systemd-sysv - you should fix your upgrade problems and these things will work again - and by the way, i would recommend the usage of lightdm instead of slim, we worked out in the last months that lightdm works far better with systemd. Switching is easy:
apt purge slim
apt get install siduction-settings-lightdm-gtk-december