Can't return to edit nodes

[Newbie1941]

I have read the manual, tried to search on here, but I think I'm just not understanding things. I'm very new to vectors.

Basically, I can't figure out how to go back and edit a node once I've clicked on a different layer. If I stay on the vector layer I can go into edit mode. But if I click on a different layer and then go back I can't see the nodes. I can select and move the shape with the pick tool. Is this suppose to happen? Seems so bizarre to me that if I even accidentally select the background layer I have to click ctrl z to get back to my vector.