You can lock Shift keyframes so that they stay in place even if you try to move them manually or perform an analysis. This is useful, for example, when you set keyframes manually and want to prevent Smoke from overwriting them when you redo the analysis.
In the following procedure, you select the keyframes directly in the image window. However, you can also select the Shift keyframes in the Channel Editor.
To lock keyframes in place:
The tracking path becomes white when you click it, and the frame that corresponds to the keyframe appears in the image window.
(a) The inside of locked keyframes are filled (b) The tracker box appears when you select a keyframe