Hello Matt.
It is just a workaround, but I work this way.
You can select the part or mesh in the viewport. So this part will be selected in the scene tree as well and the tree will be expanded. Then you should click on the selected tree entry (that is important, so that KeyShot activates the project panel). Now with the left arrow key you can navigate up the tree level.
If the project panel is not activated by selection / clicking in, the left arrow key lower the environment brightness a bit (by default hotkey settings - so you can deactivate this hotkeys in the preferences).
I work this way even in large scene tree. But I will be happy too, if someone can show us a quicker way.
Hope that helps
Cheers
Marco