I created 2 block schematic drawings then moved on to create a rack drawing in the same project. I renamed the drawing to a rack name and moved it in the tab order to be my first drawing (this was before I inserted anything into the rack layout drawing in question), SD stopped treating the particular drawing as a Rack drawing instead it treated it as a block schematic. I could not find any MA racks I needed only block schematic parts were available, the only way to solve it was to move the drawing back to it's original space in the tabs order and then all behavior was back to normal again without having to do any other changes.
 I basically did my rack drawings, once finished I moved them in the order before some schematics drawings, but wanted to report this odd behavior. Regards.