After selecting all the walls of one type in a view, when I try to deselect any of them, Revit freezes up after the deselection has been made and takes more than a few minutes to work again. What can cause this? We recently upgraded our central from 2016 to 2017. When I open the old 2016 central up, this lag does not occur. The only difference between the models is the Revit version, a small linked revit model, and 2 other people working in the 2017 model.