you create a query for t2 (let's call it t2c2) adding where clause c2 = c2parameter
you add this t2c2 query to your screen and you have a c2parameter query parameter. You also add t1 to your form.
You add t1 as a collection view (list or grid) if collection or detail if single or default.
Then you click on the left on c2parameter and on the right (properties) you bind to t1.SelectedItem.c2.
You add t2c2 to the screen as Grid.
If you want to select t1 from a combo, you add a property of type t1 in your screen and drag the property where you want. This will automatically generate an AutocompleteBox. Then you bind c2parameter to property's name.c2.
If I undestand what you want to do correctly.
P.S. Questions regarding using LS is better to be posted to
General Questions Forum. I mention this as posting to the correct forum increases the possibility to get a proper answer.
1+1 = 3 for large values of 1
