The SmartCursor can be controlled using the Data bar to lock a precise value. Once a value is locked, moving the mouse does not change that value. Enter values in the Data bar as described in
Drawing with the 2D Data Bar. The SmartCursor locks the value and no longer accepts other conflicting values. For example, enter 10 for an X value. The SmartCursor still finds Y values, but X is always 10. Most values displayed in the Data bar can be locked. Editable values have an edit box around them.
An extension line displays when I, J, K, X, Y, or delta I, delta J, delta K, delta X, delta Y values are locked. Once a value is locked, the SmartCursor no longer finds points off the line which represent that value. However, it does find points on the locked line.