Have you tried the Application Navigator? It can sometimes reveal elements that you can't spy with the mouse.
All spy modes are reliant on the meta-data built in to the target application. BP does not generate the attributes, it only draws them out of the app, and it the richness of the meta-data is not good, then uniquely identifying an element becomes difficult, sometimes impossible.
When using AA on web pages I usually find at least one of the attributes Name, Description and Role are critical.
Whilst being the least easy mode to use, Surface Automation is often a saviour when it comes to troublesome applications.