Iain, has your computer just had an upgrade to Microsoft Edge?
Mine did the auto update, then, when I clicked on the 'Vessel' or 'Port' box on Marine Traffic, nothing happened. Until I entered the name of the first ship I was looking for. They had all been wiped out by the upgrade!
That Gates fella really peeves me off - he sits at home and buggers up our computers all around the world, just because some 'smart' young underling decides it is time to confuse all us 'senior citizens' again.
Hope this helps
Skilly