Currently, there is no validate before posting Free text invoice.

System does basic validation on saving, and other validations (Period open, Customer on-hold, Ledger setup correct, Correct tax groups, default project dimensions) on posting action.

However, there is a problem when using workflow process, so we want to simulate posting before submitting to WF and posting FTI, to avoid wasting time starting process from the beginning if the error blocks posting action.