Set Sun "source angle" from widget BP

Hi all,
I’m trying to figure out why I can’t acces to source angle in a widget BP. I can get other settings like intensity of course, temperature and so on. But no acces for “source angle” settings.
Is it the expected behavior? If so, Why? (my directional light source is set to movable, so I can’t figure out why I couldn’t do it)
(I’m using 4.22.1)

The property in C++ is marked as “Blueprint Read Only”, as are most of the Directional Light properties so it cannot be set at runtime.

Is this can be unlocked in the source code? (not for me, it’s just to know!)