It has been discovered that from time to time the registry entries controlling the toolbar functions can become corrupted.  It's both rare and random.  The code has been checked carefully and no cause can be found so it's believed to originate from an external source.

Fortunately, recovering from this is almost trivial.  Within Easy-PC, go to [Settings], [Customise] and select the 'Toolbar' tab.  On this tab is a [Reset All] button.  Clicking on this will immediately restore normal function.  The downside is that any customisation will be lost, but this only affects a minority of users.