Continuing on my very large analysis routine I needed to convert a TIN to Triangles and then "select by location" on of the triangles based on its location with respect to a single point. And voila...does not work. I was going crazy, thought it was the TIN to Triangle, but then it ocurred to me to try with another selecting layer. I did and it worked. What was the difference, only that this second selecting layer has several points. Now I added a dummy point to my original selecting layer, so now it had two points, and "select by location" worked this time. Somebody there at ESRI or anybody else, could tell me if this is a bug or somebody thought this could not be usefull and thought that the selecting layer "must" have at least two features ?