According to the latest Magic Kingdom Guidemap (see scan below), the Town Square Exposition Hall on Main Street USA has been renamed "Town Square Theater". The building is currently under a refurbishment on both the outside and inside, with the interior set to be the new home for Mickey and Minnie's meet and greets later this spring. A name change to "Town Square Theater" would certainly seem to be a better theme in which to pair a meet and greet with, so perhaps this is the reason. As you can see from the photos below, the signage on the building itself have not yet been changed.