CDE exit sometimes fails (4385479)
After a user clicks the EXIT icon on the front panel to exit, the system does not return to the login screen. Instead it just hangs with a gray screen. This bug is in base Xserver (4068021, 4378762). 
Workaround: 
- 
Assume the admin role on another machine. 
- 
In the admin role, rlogin to the hung machine. 
- 
Find and kill the Xsun process.
    $ ps -ef | grep Xsun
     Xsun_proc_id
$ kill Xsun_proc_id