Any chance to get pre-selecion highligted components from script or from HDK?

You can get the cook selection from a geometry detail, such as the selection you see if you view a group SOP (GU_Detail::selection()).

But the preselection highlight during a selection operation is transient, and there is no way to access that. It does not create a selection on the geometry detail until the mouse is released.

Thanx. I mean single RED component under mouse, that highlighten without starting selection.
I dont need BLUE components during mouse drag

I see. I don't think that is currently accessible either.