window minimize in gnome

[Magnus Lawrie]

I must have pushed my browser to the limit, with too many tabbed windows 
open as the browser became exceedlingly slow and then crashed.

Now, if I minimize an application I cannot return it to the screen as 
the icon bar at bottom left is empty (a minimized application icon would 
have been located there previously).

Any suggestions how I can recover the situation? I tried shutdown -> 
restart so this appears to be a permanent alteration.

regards,