Fix NullReferenceException in CssShadowValue

[meziantou]

Types of Changes

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Description

I got another NullReferenceException

I don't know what should be nullable, so let me know if I should use ?. for other fields

[FlorianRappl]

LGTM - thanks

[FlorianRappl]

I don't know what should be nullable, so let me know if I should use ?. for other fields

I think this is fine so far - I'll anyway need to re-check all those, but on first sight this looks sufficient.

[meziantou]

Thanks! My use case now works with the latest preview :)