Ubuntu: Minimized windows vanishing ?

Recently a friend of mine started complaining that he doesn't see icons for the minimized windows on the desktop bottom panel. Any application opened from the menu will work ok, but will simply vanish when he clicks the minimize button. Upon investigation I realized it could be because the windows list applet is not visible in the gnome panel.

There are 2 methods to try to fix this. First try method 1 and if that is not solving the problem then try method 2.

1 Method 1

1. Check bottom panel for a small vertical bar with three black stripes on it - something as shown in the screenshot below (circled in red).
   
   
   Look really really hard. If you still don't find it anywhere on the panel then go to Method 2.
   
2. If you find it, right click on it and select "Move". Then move the mouse to expand the window list all the way to the left of the panel. Left-click again to finish resizing.
   
   • If the "Move" button is disabled (greyed out) and there is tick next to "Lock to panel", then click on "Lock to panel" (make sure the tick-mark goes off) and try step 2 again.
     
3. Now, you should see all the buttons of open apps in the windows list.
   
4. If not try resizing again in the appropriate direction.
   

2 Method 2

1. Right click on an empty place in the panel. I'd recommend bottom-center. Make sure you right-click with mouse on the panel (in default theme this will be a dark gray bar at the bottom of the screen). This will open the panel menu. Below screenshots illustrate this.
   
   
   • Screenshot of whole desktop with right-click on bottom-panel.
     
   
   • The right-click menu "zoomed in"
     
2. Select "Add to panel…" A new dialog titled "Add to Panel" will open.
   
3. On that dialog perform the following actions. The relevant location in the screenshot for each action in the list below is illustrated in the screenshot below.
   
   
   1. Against "Find an item to add to Panel:" type "window"
      
   2. From the list below, click on "Window List"
      
   3. Click on Add
      
4. A new window list with buttons for all open windows will be added to bottom panel. Click "Close" on the "Add to panel" dialog to dismiss it.