Previewing Mecanim Transitions from a Blend Tree

Is it possible to select which clip (or blend of clips) in a blend tree to work with when previewing/editing a transition from that blend tree state to another state? I had thought that just changing the current value of the parameters might set the animation used in the preview window, but that doesn't seem to be the case.

To give an example, I have a 2d blend tree for movement whose middle position is an idle state to smooth out transitions between the other parts of the blend tree. Problem is, when previewing transitions, this idle state is the one that it uses to edit the transition, including the preview, which is almost always not going to be the actual active animation during that transition.

Hopefully I'm not just missing an obvious setting, but I've spent a while looking for a way to no avail.