I followed the instructions here to modify my quicklists of Unity. For examples in order to add an "Root Terminal" item I modified my gnome-terminal.desktop as follows:
[Desktop Entry]
Name=Terminal
Comment=Use the command line
TryExec=gnome-terminal
Exec=gnome-terminal
Icon=utilities-terminal
Type=Application
X-GNOME-DocPath=gnome-terminal/index.html
X-GNOME-Bugzilla-Bugzilla=GNOME
X-GNOME-Bugzilla-Product=gnome-terminal
X-GNOME-Bugzilla-Component=BugBuddyBugs
X-GNOME-Bugzilla-Version=2.32.1
Categories=GNOME;GTK;Utility;TerminalEmulator;
StartupNotify=true
OnlyShowIn=GNOME;Unity;
X-Ubuntu-Gettext-Domain=gnome-terminal
X-Ayatana-Desktop-Shortcuts=Root;
[Root Shortcut Group]
Name=Root Terminal
Exec=gksudo gnome-terminal
TargetEnvironment=Unity
And then I dragged it to the launcher. It worked fine before rebooting. But after the system is restarted, the Terminal button launcher is reverted (No Root Terminal after right click), despite of the desktop file has been modified.
So what steps do I miss? Thanks for those who gives hints.