The Holding Valuation Pod displays the aggregate holding value across all your portfolios over time.
The valuation line displays your holding valuation including changes to market value
The contribution line displays the investments and redemptions you have made
The area where the valuation line exceeds the contribution line represents a gain on your investment
The area where the valuation line is exceeded by the contribution line represents a loss on your investment
The current gain/loss on investment is displayed at the top of the Holding Valuation Pod.

This Graph may also be accessed via the Fund Holdings screen which allows you to change the graph view to:
Display data for a particular portfolio
Display data for a particular period of time