Reselect item in parent sidebar when child sidebar is closed

[kylesayrs]

Steps to Reproduce:

1. Click on a node
2. Click on a tensor or connection
3. Close the tensor or connection sidebar
4. The node is not reselected on the graph in the same way you'd expect if you clicked on a node through a connection sidebar

[lutzroeder]

@kylesayrs can you submit pull requests to address these issues.

#1298