If you are using AutoCAD® Architecture 2015 and 2016, you place AEC Objects on layers other than the layer associated with the default Layer Key for that object type and you have occasion to turn off and/or freeze the layer associated with that default Layer Key, you may have found that simply selecting one of the objects on one of the other layers will result in the layer associated with the default Layer Key being turned on and thawed. This makes it difficult to work with just the items on the "other" layers. One situation where this would be desirable is on a renovation project, where you have the existing-to-remain, existing-to-be-demolished and new construction objects all in the same file, and you want to view and edit the demolition plan. To do so, you would turn off and/or freeze the new construction layers, and would not expect these to turn back on and thaw just because you select an item on the existing-to-remain or existing-to-be-demolished layers.
For example, you may have a file where the WALL layer key is associated with a layer named A-Wall-N, on which new construction Walls are placed. A layer named A-Wall-E is used for existing-to-remain Walls, and existing-to-be-demolished Walls are placed on a layer named A-Wall-D. As seen in the Screencast below, if the A-Wall-N layer is frozen and turned off, selecting a Wall on the A-Wall-D layer will result in the A-Wall-N layer being turned on and thawed. A REGEN is needed to see this immediately, since the layer had been frozen, but you can also check the Layer Properties Manager to see that the layer has, in fact, been turned on and thawed.
The 2014 release did not exhibit this behavior, as shown in the second half of the Screencast. Note also that if you select multiple object types at one time, only the layer associated with the default Layer Key of the first object type selected will be turned on/thawed.