I am looking for a functionality like when i click on the 1st option(in attached qvw) only then second should b activate but what is happening in my case those option which dimension objects which are not present for that selection are grading out but i can select those, i want they should appear but user will not be able to select those.
In the properties of the top list box select "Override Locked Field". Then make a default selection (e.g. LL1) and lock the field.
Because this field is locked, you cannot make selections in other list boxes that go against the current selection in this field. However because you have set this field to "Override Locked Field" you can make new selections in this field without unlocking.