Why can't I move a file across projects?

[yix]

I have edit access to two different projects, why can’t I move a file between the two projects?

[VincentF]

You need to be owner of both projects.

[tps]

The specific reason you need to be owner of both projects is that since each project has separate security / access configurations, moving a file is akin to changing who has access to it – and access / security changes in a responsibility of owners.