In Blender 2.8, we support having multiple objects in Edit Mode, Pose Mode and Sculpt Mode.
In order for this to work well, we want to make it more clear which objects are in the mode session, and also make it easy to both add & remove items from the current session.
We want to solve this as follows:
When in either Edit Mode, Sculpt Mode or Pose Mode, the objects in the mode stand out, like so:
In the Outliner, we will add an additional column with an icon corresponding to the active mode. When you click it, you can toggle that item in and out of the current mode:
Also, we make the items in the mode prominently stand out with a differently colored row.
In object mode this column wont be displayed.