Purpose
To enable the movement of a control point in both the time and value directions, or individually in either time or value.
Usage
Click the time/value toggle button. The toggle button text will change to time. Click the toggle button again and the text will change to value. Click once more to return to the original text. (Similar to the xy button in the transformation menu.)
Comments
Use this toggle button if you want to move a control point only in one direction instead of two, which is the default.
See also
move point