Render files not deleted
When I finish a project, I do File->Delete Generated Library Files and tell it to delete everything.
When I look at the fcpbundle contents (after exiting FCPX) I see that it did delete the "Transcoded Media" content (proxies and optimized media), but in the Render Files, there is still lots of stuff there (1/2 a Gig in the Thumbnails directory, way less in the Peaks Data, but it's certainly not empty).
Is there a reason for this? Thanks.
MacBook Pro, macOS High Sierra (10.13.1)