Holbek's 'Europa' music plagiarized by Howard Shore for 'The Aviator' ?

Plagiarism in music is as widespread as in literature and academia,
but rarely gets the public attention it deserves:
Only when composers sue in court, we sometimes get a little media attention,
like with the notorious plagiarism by 'Led Zeppelin' and others.

Where does plagiarism in music begin?

Howard Shore is without any doubt a good composer and I like most of his soundtracks.
But how 'original' are his 'Original Soundtracks' really ?

Two cases are especially interesting:

1) "The Aviator"(2004, Martin Scorsese):
An important leitmotif of Shore's OST is nearly identical to music
by composer Joachim Holbek in "Europa"(Lars von Trier, 1991).
It's a very distinct piece of music you'll recognize fast in both movies.
Howard Shore won the Golden Globe for 'Best OST'.
Joachim Holbek is not mentioned in the credits of "The Aviator"; at all.
"Europa" was distributed in America and is a well-known arthouse film.

2) "The Silence of the Lambs"(1991, Jonathan Demme):
Again: An important leitmotif is nearly identical to music by
composer Frank Cordell in "God told me to"(Larry Cohen, 1976).
Again: Frank Cordell is not mentioned in the credits of "God told me to" at all.

I'm not a composer, only an avid cinephile and sometimes fan of Howard Shore.

To my ears it clearly sounds like plagiarism since Howard Shore seemingly
took music from other composers without giving them due credit.

Comments?