iMovie Library file makes no sense

[Mjmar]

With iMovie 10 there was the introduction of an iMovie file called iMovie Library that contains all of your iMovie data in one file... Or at least thats what I thought until I deleted it. For some reason when I deleted it there was no space freed on my hard drive and I'm not sure why considering the iMovie Library showed that it was taking up 75 GB. I have emptied it from the trash, and even restarted my computer - yet none of the space has opened up. Can anybody explain why this is happening? The only thing I could think of is that the file was just linking to the iMovie events folder that was used by the older iMovie; however, Apple claims that once you upgrade to iMovie 10 you could delete the iMovie events folder since it creates the iMovie Library file. So confusing.