I assume the issue is that you have the Dropdown setup to use Picks and the Foreach loop is looking at Things. Either change your dropdown to look at Things or change the foreach loop to look at Picks. But currently you have apples looking at oranges and wondering why they don't match.
Another way is to take the dropdown out of the equation and do the following:
Code:
foreach thing in Ability where "abCategory.Inh_tal"
debug eachthing.idstring
nexteach
Then go to
Develop->Floating Info Windows->Show Debug Output. This will open a window that will show you the Thing ID from the above Debug statement.