This could be useful but could also be annoying to some users. It's hard to say where the balance is, and in cases where things aren't clear-cut, adding a new feature is unlikely. That being said I think there's an easier workaround for your particular need which is to simply use the Stay Open button on the pop-up node settings windows. Double-click a node in the network and its settings come up, click the Stay Open button at top-right, then double-click the 2nd shader and do the same (Stay Open). Now you can compare side-by side, copy back and forth, etc.
- Oshyan