@Romuald I have been using ONE for about a year after OV shut down and fairly comfortable in using it ...... brand new SO member and I have "backtested" a few previous real trades to get a feel of they work as price, time and IV change throughout the length of a trade .... one comment and one answer for you
you can close a trade with one click of the "grid" icon between the red X icon and the magnifying glass icon as shown below ... this will insert an entry in the model column offsetting the positions you have ... follow that up with clicking on the Commit icon and the closing trade is entered
this statement is clipped for the ONE online manual
the daily movement of the Position's overall value as the Underlying vehicles price fluctuates over the current trading day - shown by the scattering of green dots (which are based on actual intra-day prices throughout the trading session) - shows that there is a considerable amount of movement on a daily basis.
in the case of a risk chart for a backtest I believe the dots are a scatter plot of trade's mid price at 5 min intervals throughout the day .... you will also see red dots in some cases ... the green dots are prices at which trade is positive and red dots are prices at which the trade is negative ... you will also see a slightly larger light blue dot and that is the price at the moment in time you are at as you step through the backtest
hope this helps