@Gary, Here is the procedure, Next to the Terminal Window icon (on top) , right-click
choose 'Add to Panel'.Now you'll get a 'Add to Panel' dialog. Choose 'Quit' under
'Desktop & Windows'
See ScreenShot
Now click on the 'Add' button. Now you'll
get the 'Quit' icon on top. To take a Screenshot of the entire screen press 'Print Screen'
button. If you want to take a screenshot of a dialog Window only , then point the
mouse over the dialog Window , press 'Alt + PrintScreen' keys. This will take the
screenshot of the dialog Window only.