When the reference point
            is temporarily covered by another object, position the tracker manually.
         
         To manually position the tracker box:
         
         
            - Click the Analyze Forward button to stop
               the analysis.
            
- Advance the clip to the frame where the
               reference point becomes visible again, and reposition the tracker
               box over the reference point.
            
- Click Analyze to restart the analysis
               at this frame. Since the X and Y shifts are recorded as keyframes
               in channels, the translation values for the frames in which the
               reference point was covered are calculated. The final result will
               be a smooth motion.