Prevent throwing warnings for nodes with required but disconnected ports

Hi,

when placing a node like the Value Lookup, whcih requires two ports being connected, a warning / error is immediately thrown (false-positive):

Invalid node settings
Loading the saved settings failed. Falling back to default settings.
First error: String for key "mode" not found. 

That causes unnecessary distraction and log bloat. I’d like to suggest to trigger validation only when minimum criteria, like all mandatory ports beign connected, are satisfied.

Best
Mike