nightly builds : measure style

I open a muse score 1.2 file in nightly builds 5654
It is a 3/4 mesure, and in the mesure properties it is said 6/8 ......
(I don't have a mesure change , just one mesure in "real time" 29/32)

I wondered that because beam looked like 6/8 ........

how can I change a lot of mesure from 6/8 to 3/4 in one time ? is it possible ..???