Raspberry Pi is typically connected via ssh character interface to use, or use the vnc connection. Occasionally we encounter the situation stuck desktop process, specific performance is no response icons and taskbar button, but the CPU load, etc. everything is normal. This situation, in addition to restart the machine, it can also be repaired through a graphical interface to restart the process.
First, the incoming character ssh connection terminal
pi@DEX54-PC:~ $ ps -t tty7 PID TTY TIME CMD 9493 tty7 00:00:14 Xorg
(Tty1 ~ 6 is text-based console, tty7 is a graphical X Window Display Manager, a graphical interface where we find the corresponding process pid)
pi@DEX54-PC:~ $ sudo kill 9493
At this point if connected vnc, you will find short dark screen, desktop wallpaper and then reappears, and a login box, enter the password Log in, can return to normal.
In the final analysis, it is to restart the X server, because the raspberry default, it lightdm as X service manager, so the final step to restart lightdm also possible.
pi@DEX54-PC:~ $ sudo service lightdm restart
The above method for the browser window to force the end of the file (raspberry pie in the default file manager for the PCManFM, because using the LXDE desktop environment) lead to the disappearance of desktop icons is workable.