How can I determine if a visible row of a TIB_Grid is selected?

The problem I have is this:

I open a form with a grid and a searchbox, the active entry of the gird is the first one.
Now the user types some search criteria, this may result in only one entry left in the grid.
Since this may be the (only) one the user is searching for, he clicks on the select button w/o clicking first onto the entry in the grid to make it the active one.
Hence, the wrong entry gets selected.

Florian