Include Unbilled Projects
If there are project timeslips, expenses or estimates you haven't yet billed your contact/client for, you can include them while setting up a new invoice. But you can also choose to format each of these on the invoice in different ways, so there's a fair bit of content to be displayed as a result of simply checking a project.
Here I'm trying to stagger the introduction of each content block (and switch out the form comment/hint - still janky) so it feels a little easier to digest. If the 'Timeslips', 'Expenses' and 'Estimates' options weren't checked on when revealed it'd be much easier to digest, but that'd mean having to check them all back on again if you did indeed want to bill for them all (the likely case).