Line tool
Use the Line tool to make logical connections between objects. Once two objects are connected, they stay connected no matter how much you move them around or change them.
Lines can have line labels attached to them. Drag a shape object to the line until the line is highlighted, then drop it to attach it to the line as a label.
To create a new line:
Click where you would like the source of the line; this can be an object (to which the line will stay attached) or an empty spot on the canvas (to leave the beginning of the line unattached).
Click as many empty spots on the canvas as you like to give the line midpoints. The line will pass through these points on its way to the destination. If you do not create any midpoints, the line will go directly to its destination.
End the line at an object by clicking the object (to which the line will stay attached), or end the line at an empty spot on the canvas by double-clicking there.
Hold Shift while drawing a line to constrain the next point to angles at 45 degree increments from the previous point. Hold Option or Command while drawing a line to prevent it from connecting to objects.
When two objects are connected by a line, the object at the source is considered the parent of the object at the destination. This defines the objects' relationship in the outline view and when you use the automatic layout functions.