2D Placer is a tool for placing Detail Items and Annotation Symbols. The motivation for creating the 2D Placer is because the standard method for placing such components involves picking an item from a rather small list with all of the families and types expanded. It can take a while to find the family you are looking for if a bunch of families are loaded.
2D Placer provides a simple and useful interface for finding the 2D component that you want to place. There are two list boxes for picking. The left box contains all of the Detail Item or Generic Annotation families that are loaded in the project. Once a family is selected, the right dialog populates with all of the types loaded. Pick the type and place it.