Note that the version 3.4 will introduce a new Select object submenu in the contextual menu of the plan that will let you select an object among the superimposed ones that appear where you clicked.
That's good news. But such a submenu would be even more useful if it would list also the wall, at the bottom (if all objects are sorted by elevation).
EDIT: nevermind that
I'm checking up the beta right now and I see that's already done. Great job.