Once an invoice or bill is excluded from the cash flow it will no longer show in the main cash flow table, it will only show in the 'Invoices Due' or 'Bills to Pay' section. When you first access these sections the excluded items may be hidden from view, however these can be shown with one click.
While in the 'Invoices Due' or 'Bills to Pay' section scroll past the overdue table to the upcoming table (if you don't have any overdue invoices/bills only the upcoming table will show). Just above the right side of the table you will see an option 'Display excluded invoices'.
With this option ticked the excluded invoices/bills will show in the table, if it isn't ticked they will be hidden from view. So if you wanted to include any excluded invoices/bills just tick the option to show them, select the relevant invoices and you can then untick it to hide any that are still excluded.