gnome shell dock goes blank
Sometimes the Gnome Shell dock (application launcher strip) goes blank.
To get it back without logging out and back in:
Press Alt + F2
Type r
Press Enter
This will restart GNOME Shell while keeping your applications running.
To do this in a shell script:
#!/bin/bash
dbus-send --type=method_call --dest=org.gnome.Shell /org/gnome/Shell org.gnome.Shell.Eval string:'global.reexec_self()'