Add icons in desktop panel
If you want to add icons in Desktop panel follow the below steps.
Example:Add thunderbird to ur panel.
(*) Right click panel-> select Add to panel.
(*) Select Custom Application Launcher -> Click Add -> Create Launcher Dialog box will open.
(*) Set Type as Application, Name as Name of the application(thunderbird) and Command as full path of the application.
(*) Set Icon and click Ok.
Another way is,
(*) Select Applications-> Select Internet -> Select Thunderbird-> Right click -> Add this launcher to panel.