You can probably set a field in the invoice record to mark it as printed. I would recommend that after the printing it done, you prompt the user to mark the record or not. This way they can check that it printed correctly first.
You can use a simple number field to mark it with a 1 if it printed corrected. Then your conditional formatting would just refer this field. Since the conditional formatting evaluates with a boolean check, if the field has the one in it, it will make it true.
BTW, why is this in the Report bugs forum?
Moderator can we move this to the right forum?
I'm reading it in the "Using FM" forum!
Yes because TSGal moved it. ;)
Yes, I did move the thread, and I should have posted that it was moved. Sorry about that. I'll try to remember next time.