Unrealized Profit/Loss for the account is calculated by Interactive Brokers and displayed in MultiCharts.
In order to include the "Unrealized P/L" value from TWS '''FX Portfolio - Virtual FX Position''' into "Open P\L" value of Order and Position Tracker Window -> '''Accounts tab''' it is essential to enable "include FX position when sending portfolio" selection in the TWS > Global Configuration > API > Settings.