Back-adjustment is the ability to adjust the data of previous contracts in a continuous in order to remove the roll gap due to price differences for different contracts.
The adjustment is implemented in the following way: when the continuous is switched to the next new contract, all previous contracts are adjusted according to the coefficient, which is calculated as the difference between the Close of the new and old contracts for the nearest daily bar to the switching point in the continuous. Usually these are daily bars preceding the switching day to the next contract.
By default, back-adjustment is disabled. You can enable it on a chart with a continuous in two ways:
If the b-adj button and the Adjust for contracts changes feature are not available for the selected futures, then this feature is not yet available for these futures and will be available in the future.