Field help (GASDEB) 

Enter an amount if the entry line is a debit.

The default sense is set up in the account file. If the default account sense is not determined, the cursor is positioned on the field that is used to balance the journal.

The journal must necessarily be balanced in the transaction currency. A rounding variance line is generated automatically in order to balance the journal in the ledger currency if necessary.
For a cash journal, the offset is generated automatically.
The button [Currency] is used to visualize the amounts in the stored currencies.

Three options are proposed using the right-click menu: