So if I understand what you are describing, you have a column much like this on the table you created:
If you created it in a scoped app, it would not have the u_ on the front of the u_active.
If this column exists, I can't think of a reason that you cannot include it in a UI Policy condition; however, notice that I included Active on the Active column. Check that on your Active column and see if it is true. If you created the table and added the field, I don't think it would be deactivated, but you never know.
This would be a guess as to why a field that is on a table would not be available in the condition of a UI Policy for that table.
The other possibility is that you have the wrong table. Note that you can have a Label on a table that is duplicated so if that is the case, you have to take note of the table's name contained in the []'s for most table displayed names.
