For a while, the simulation tool has been currency agnostic - whatever currency you entered in was fine as long as you were consistent throughout the entire form.
However, with the addition of specifying your assets via stock tickers, we needed to adjust the currency of those stocks to the ones you were reporting.
You now have the option to select the base currency you want to work in at the top of the simulation. From that point on, when you enter tickers for stocks you own, the market values will all be converted to their equivalents in your chosen base currency.