The “Normalize” settings ensure that all currency pairs within the watchlist have the same base currency.
A simple example is to look at the “GBP Pairs” watchlist.
You’ll notice that all currency pairs have “GBP” as the base currency, except for EUR/GBP.
If you were to look att he 12-month performance for all the GBP currency pairs, you’d see that they’re all positive or “green”…except for one…EUR/GBP.
That’s because “EUR” is the base currency, so even though GBP appreciated against EUR, the graph shows negative or “red”.
By “normalizing”, all currency pairs within a watchlist can be evaluated the same way.