Despite the small print on the Portfolio Valuation page, the way it actually works (at least for me) is to show the value and increase/decrease of current holdings based on the shares or units that have actually been purchased initially and subsequently. It does not assume reinvestment and under the Cash section I keep a note of my cash in broker accounts. I prefer it this way as I do not automatically reinvest any dividends.
The Analyse Asset Allocation tab does, however, give you total return numbers overall and by individual holding.
A weakness of the system is that at least for me the Asset Class numbers seem to be inaccurate and incomplete, but I can get those from Morningstar on my ii accounts. Another issue is that the system only gives you a snapshot of current holdings, but that is in line with most broker accounts.