Grid is still showing old rows when creating a new record on form

Hello All,

I have a custom form with grid. when i am creating new record on form by clicking new button(form new button not grid new button) , this grid rows remains same what i have added in last form record. grid should come empty with no row so user can add rows according to the respected record.

How i can make this grid empty , when creating a new form record , please advise. i guess there is some property need to be set for this.

Here is my grid below

It seems that this issue has been resolved in a duplicate thread in another forum.