I have a problem trying to filter a lookup field ad I need some help.

Let's say I have a form called Form1 with just one lookup field called Lookup which "points" to a second form called Form2 which has a numeric field ( Form1_ID) and a text field ( Text).

When I edit a record based on Form1, I want to filter Lookup with this criteria Form1_ID == input.ID.

I don't understand why it doesn't work (the dropdown list is always empty).

If the criteria is something like Form1_ID == xyz (where xyz is the ID of a record based on Form1) it works, but if instead of  xyz i specify input.ID it doesn't work.

Where is my mistake?

Thx,

Michele