Added check for nullptr before accessing baseData. Only clear property list if data types differ but base data is not null.
Added check for nullptr before accessing baseData.
Only clear property list if data types differ but base data is not null.

MITK/MITK,RabadanLab/MITKats,RabadanLab/MITKats,fmilano/mitk,MITK/MITK,iwegner/MITK,iwegner/MITK,iwegner/MITK,RabadanLab/MITKats,MITK/MITK,NifTK/MITK,fmilano/mitk,RabadanLab/MITKats,NifTK/MITK,fmilano/mitk,fmilano/mitk,MITK/MITK,iwegner/MITK,iwegner/MITK,fmilano/mitk,iwegner/MITK,NifTK/MITK,fmilano/mitk,NifTK/MITK,MITK/MITK,RabadanLab/MITKats,MITK/MITK,NifTK/MITK,NifTK/MITK,RabadanLab/MITKats,fmilano/mitk