If the tracker loses the reference point, you can delete the incorrect keyframes, then, at the last good keyframe, update the reference point to the current contents of the tracker box.

To update the reference point to the tracker box contents:

1. Select the appropriate tracker by clicking the appropriate Tracker button.
2. Press Backspace.

   The last keyframe is deleted and the positioner moves back one frame. The tracker box is now on the previous keyframe.

3. If you want to remove this keyframe, press Backspace again.
4. Repeat step 2 for all incorrect keyframes.
5. When you reach the last good keyframe, click Snap. This updates the reference point from the one originally specified in the reference frame to the image currently inside the tracker box.
6. Click Analyze to continue the tracking process.