This dialog box is called from the invoicing plan window and is used for creation of project invoice based on the selected lines. You can choose to include transactions on project or sub project level for the lines you have selected. Unique invoices will be created for invoices lines and transactions which belong to projects which have the Project Unique Billing check box selected in the Project window. For such invoices, the Project ID field on the invoice header will automatically get the ID of the project.
Note: Transactions with negative amount (credit transactions) will not be included when selecting the option Include all normal transactions. If you want credit transactions to be included, this must be made manually by selecting Add to Invoice from the Project Transactions window.