Best Supporting Actress 1945: Angela Lansbury - The Picture of Dorian Gray

Some time ago I had to read a shortened version of The Picture of Dorian Gray to school, so I didn't enjoy the film very much, because it couldn't surprise me, but it was fine.

Angela Lansbury's character of Sibyl doesn't have a huge presence in the film. She spends on the screen very short time and if I said Eve Arden didn't have very much to do in Mildred Pierce, Lansbury has nothing to do. She's only there to be charmed, then happy and then sad. But almost the whole time of her performance she keeps the same innocent face. She showed us her character half-sidely. Everyone has its good side and the bad side, but Lansbury's portrayal made Sibyl to be only good.
But a little bit I understand this way or portraying. Sibyl was supposed to be the first good thing Dorian meets in his life. The film didn't give you many possibilities to show us Sibyl as a person, but she didn't even try.
Her best moment would probably be her first scene, where she is singing and she sees Dorian the first time.
In the end I must say that Angela Lansbury wasn't actually bad in The Picture of Dorian Gray. She was good. But I don't think her performance was something that needed to be awarded...