The Assign Controller rollout has been modernized with options to help animators work more efficiently.
The Motion Panel Assign Controller Rollout has been improved so that the panel is responsive and resizes to correctly fit the length and width of the Command Panel. A new, expanded, context menu has useful functions to let you copy, paste copy/instance, paste to Wire, assign, reset the Controller to default, and show in Track View.
These changes build on recent animation controller improvements, the new Transform List controller, and other UI updates.
Also the Assign Controller Rolloutnow shows the selected node as the root of the tree view instead of only the transform of the node, similar to how it is displayed in the Track View. This way you can view the node, modifier stack, and the assigned material, with attributes updating as changes are made. Also similar to the Track View, you grab the list to navigate the tree view.
The Motion panel Assign Controller tree view
Aside from providing an intuitive user experience, these enhancements provide playback gains when the Motion Command Panel is open.
New Assign Controller Dialog behavior