The German version of "Dot all the I's and cross all the T's." To make sure something is done in the proper manner, without even a minor or technical error.
During John Demjanjuk's trial for his infamous WWII-era war crimes, the prosecuting attorney had to make sure to dot all the umlauts in every motion he made before the court.
Umlaut
Umlaut
by The Fourth Man in the Tub May 13, 2011