The Trade History table will show you all current (shown as either 'Open' or 'Partially Closed') and past (shown as 'Fully Closed') positions. Traders may see trade history directly on the trading page, or navigate to Account to view complete historical data.
Clicking anywhere on each position row will bring up this pop-up window showing the detailed history for that given position in an accordion style format. You will be able to see any partial closes including dates/times as well as realized P&L and % of the position closed for each. On top of that you can also easily see when any collateral and/or position modifications were made.