strange behaviour of file-sync in IDEA 11

Hi list,

i recognize kind of strange behaviour of file-sync.
When i add or delete files outside of IDEA (directly in the folder e.g
via finder) i am used to seeing these changes in IDEA after a short delay.
But recently i cannot synchronize IDEA project with directory. Even when
i manually try to synchronize folder it stays as it is.
Is this a kind of caching? I cannot remember this behaviour in previous
versions of IDE.

Is this a known issue?
Can i get around this anyhow?

Regards,
Tilman