Partial Qty field remains blank in OD

Hello,

I created an Outbound delivery & when i click Packing Icon, in the next screen, I see that partial qty field remains blank(In the Material to be packed section).Can anyone tell me what is the reason behind this & what needs to be done to have the qty appearing in the partial Qty field.For further Info, I haven't started the packing yet.

Thanks

Regards

Goutham