If you want to select, say, a cluster inside an array, you have a really narrow range of pixels to target. If you click in the body of the cluster, it selects the array. If you have a cluster in a cluster, it doesn't select anything to click blank space inside the cluster.
Attached file indicates what I'm talking about. If you want the green line, that's pretty narrow. Many people may be able to handle that degree of precision. But some people may find it hard to point that precisely.
SO, it'd be nice if you could select anything in the containment hierarchy, and discretely adjust your way to the right thing. I suggest that tapping shift would select the parent of the current selection. Tapping ctrl would select the child of the current selection that the mouse is hovering over.
Like, select the inner array and tap shift, and the selection is now the cluster it's in.
Showing this as an option in the contextual menu, with the shortcut indicated to the right, would be a good way to introduce this to the user - "select parent (shift)", "select child 'childName' (ctrl)"
