Which preposition to use with showcases

on Occurrences 1%

The Massachusetts Woman Suffrage Association has a showcase on the sidewalk in front of its headquarters where it displays pictures, clippings, novelties and anything that may capture the interest of the passing pedestrian.

with Occurrences 1%

Back of the showcase with the rest of us, waiting on trade, and looking like a Yale yell.

Which preposition to use with  showcases