Window lost when minimising on netbook

[welshmike]

The problem is my fault for fiddling with the panel on my netbook.

When I minimise a window its icon does not appear in my netbook's panel and I am not able to get the window back as there is no ic`on to click on in the panel.
The icon (for Firefox in this example) does appear on my laptop's panel.
Please see images below:
Netbook
http://www.colcomcomclub.org.uk/netbook.png
http://www.colcomcomclub.org.uk/netbook.png
Laptop
http://www.colcomcomclub.org.uk/notebook.png
http://www.colcomcomclub.org.uk/notebook.png
How may I get the icon to appear in my netbook's panel please?