I change background wallpaper, add an another panel at top, add some link/ applet, install some application. Suddenly I found that the bottom panel/ menu bar has vanished. After searching at preference, I took help of Google and found a topic at Peppermint OS Forum. At that forum a user asked that Where did the menu bar go? (Noob) (MIA). I learned that I need to reconfigure dpkg.
Codes are written below according to the Peppermint Forum.
Code:Famous Peppermint moderator Rich Roast wish that it will solve the preblem. If this kind of issue rise in Peppermint Ice then addresses will change. He also said that "the above is a guide only"
sudo dpkg-reconfigure peppermint-default-settings
sudo dpkg-reconfigure peppermint-ice-default-settings
alternatively the (hidden) ./config skeleton folder to restore is held at /etc/skel; copy its contents to ~./config folder
cp -r /etc/skel/.config/* ~/.config
and then some other things installed to /usr/share:
cp -r /usr/share/lxpanel/profile/Peppermint/* ~/.config/lxpanel/Peppermint
cp /usr/share/peppermint/openbox/* ~/.config/openbox
cp /usr/share/peppermint/pcmanfm/* ~/.config/pcmanfm
I applied that suggestion and solve the problem.