Seems like it is still broken for nested widgets with more than 2 hierarchy layers,
For example,
UserWidget
=> BP_GenericUsableWidget (has IA_<…> nodes handling)
=> BP_ActualWidget (does nothing input related, but wants to inherit parent functionality)
In this case, the BP_ActualWidget will be broken and won’t receive any input at all (which is handled by parent BP_GenericUsableWidget ). And when you are adding any input node to it, you are getting the validation error about bAutomaticallyRegisterInputOnConstruction (without specifying what am I suppose to do with it).
I’ve tried all code snippets in this thread, but unfortunately, only adding the dummy node to the final BP, getting through the validation error, and resaving the asset worked for me. Which is still a disaster, because we have like 50+ inherited BP’s.
Also, simply reverting the change from https://github.com/EpicGames/UnrealEngine/commit/5d2571bb36ab37410643e12d5a20909cc95d81c3#diff-879cdb73bf83a7b4857cc5593d56304e51262a774f5deffffc04fb8f3cb8d41aL1715 fixes the issue