It is the night of Purim and for some reason the majority of the Shul has not yet said Kiddush Levana. Should Kiddush Levana be said prior to Megila due to "Tadur" it being more frequent? (source)
Noda B'Yehuda 41 - page 44 - column starting with Vnashiv says that they should make Kiddush Levana first for two reasons. One is tadir. The other is that the Megila can always be done later, however Kiddush Levana there is a risk of it getting cloudy.