Hi again,
i finally found out what the problem was. I think for a newbie this is a big obstacle, and it gave me headache for at least two weeks until i found a post with a similar question on reddit.
Around the nodes i posted above there are some other nodes in higher hierarchy of control type. Controls have a category mouse and a property Filter (docs: mouse_filter). Don't know if others have that also.
The default value is set to Stop (others values: Pass and Ignore).
Set to Stop prevents the mouse event being passed to other nodes.
I had to check all of my nodes and set the Filter property to, in my case Ignore, after that my mouse click and the correct object where recognized.
Hopefully this info helps others.
regards
Antonio