I just had to register, just to thank you all for making it even more complicated for/to me (I question everything right now), at the moment I'm Dutch and what I was looking for myself, before seeing this thread, came from this paragraph:
After having served as the largest port in the world for 42-years between 1962 and 2004 before it was surpassed by Singapore and Shanghai, The Port of Rotterdam is still the biggest port in the European continent.
Given the fact a lot of times the correct Dutch spelling is similar to the English version, this time not. We would use: 'biggest port ON the European continent'.
But when I looked it up for the English spelling, to make sure, I saw an explanation that when the continent name is mentioned, then you use IN. They also tell: "When the word in front of it ends with -ing, it's always "ON".
Of course when I then look up whether we Dutch make that distinction in case the name of the continent is in the text...they didn't mentioned that Here the original and English translation.
Going to make some lunch, in my kitchen, on my plate.
Cheers, maybe I will look later on myself but will surely bookmark this page to see if any addition to either the island or continent question.