The Select And Manipulate tool lets you edit the parameters of certain objects, modifiers, and controllers by dragging "manipulators" in viewports.
Note: Unlike Select And Move and the other transforms, this button's state is non-exclusive. As long as Select mode or one of the transform modes is active, and Select And Manipulate is turned on, you can manipulate objects. However, you must turn off Select And Manipulate before you can select a manipulator helper.
You can add these custom manipulators to your scene:
Cone Angle Manipulator
Plane Angle Manipulator
Slider Manipulator
These features have manipulators built in, which you can use to change parameters on these objects:
IK Solver Properties Rollout (HI Solver)
Reaction Controllers
Target Spotlight
Target Directional Light
mr Area Spotlight
Free Spotlight
Spotlight Parameters
UVW Map Modifier
Primitives with a Radius parameter have a built-in manipulator for the radius.
Caddy Manipulators
When Select And Manipulate is active, the caddy appears in certain sub-object contexts for convenient access to settings. These include:
Tip: You can toggle the availability of any individual setting in the caddy manipulator with a checkbox setting that drops down from the respective ribbon control.