Corrected defect:  In all 3D registrations 2 documents should be present.  The selected document is used as a Target of the registration.  However, if more than 2 document are present, the selection of Source document is sometimes incorrect.  Now the warning would be issued when more than one possible Source document is present.

Added new UI function:   "MainMenu>Volume>Crop4D - Current dynamic point only"

Fixed the defect of gross misregistration in liver DCDI exam.  New default setting for all parameters were explored and set.  All the gross misregistration cases are fixed. Results are not stellar, but for large proportion of timepoint the movement across the axial plane is greatly reduce.
Further work will be done as needed but result is good enough for now.