You should see a label called Modified Object . Click on Modified Object . It is tempting to think that we want to animate the Height attribute of the blade cylinder. There is a small problem with animating height in tandem with the current hierarchy. The linkage passes transformation information along the hierarchy.
Height is a creation attribute of the blade cylinder.
Changes in the height of the cylinder will not be passed along to the blade tip. The lightsaber blade will retract, but the blade tip will remain fixed. If the handle is moved or rotated, the retracted blade will move and rotate. That information will be conveyed to the blade tip. What you obtain is a tip that maintains correct orientation, but only to the end position of the original blade.