Psak From Reb Shlomo Miller -Trying On Shatnez

According to Mori V'Rabi Hagaon R. Shlomo Miller Shlita,

when trying on Shatnez garments  , you may do so

only if you don't have Hana'as Levisha (benefit  in wearing)

You may try it on, for size or looks.

When trying on, pants skirts etc. being it's embarrassing

to walk around in public without them .It is considered Hana'as 

Levisha.if you leave the dressing room.(public area)

Therefore you may not leave the dressing room while wearing

these types of Shatnez garments..