I suggest you use the Portfolio. Investing->InvestingTools->Portfolio will get you there, but it
is better to add Portfolio as a Shortcut to get you to the Portfolio in a single click.
In the Portfolio view, click "See a different view" on the left.
There you can Customize a view to include various choices of data.
Some will appeal to you more than others.
ChangePortfolioView->CustomizeCurrentView->PortfolioColumns
I suggest the CostBasis column to see what you paid for your current holdings of a security. The Appreciation column tells the difference in what you paid vs the current value, to the extent that Money knows that value. The Gain column is similar, except
it includes dividends. There are other useful column-- particulary the various TotalReturn columns for various time periods.
Now if you are looking for something else, what do you want to see? Suppose you bought 100 xyz @ $10 per share and later bought 50 more shares @$11 per share? Are you just looking to see $1550 for xyz displayed or what? I am not sure what distinction
you are making for gain, unless you are asking for the gain for things you still hold vs the capital gain for what you already sold.
Anyway, Portfolio is the thing to use generally.