I am a bit of a fossil as far as computing is concerned an avoid filling the screen with icons but work with a menu - thanks to Classic Shell. I do have five heavy usage programs pinned to the Taskbar and have several icons displayed in the Notification Area. These are programs with animated alerts which are useful indicators.

Over he past few weeks these icons have sometimes started disappearing and I have had to customise the Taskbar and change the required programs to "Show icon and notifications". However this is now occurring more frequently and, in fact, almost daily and I would be grateful if someone can explain the phenomenon and, hopefully, provide the necessary fix to ensure that is stops behaving in this annoying manner.