Selection of atoms

Hi there,
Currently i am unable to select/deselect atoms in DSvisualizer 2, which can be useful in finding the bond distance, selecting a particular residue..etc. I am using linux felicia 6 as my OS, I have also tried reinstall DSvisualizer 2, but still i am unable to select/deselect atoms. Is there any settings or preferences to be configured/changed in DS.? I know that this feature can be supported and will work well in the same OS or higher.
Can any one help me out.