Cannot copy to top level in tree view

[Andreas Heinlein <aheinlein gmx com>]

Hello,

I use the tree view in the sidebar most of the time. Sometimes I want to
copy a file to a removable drive, but cannot simply drag it to the drive
icon in the tree view, i.e. the top level of the drive. I can expand the
drive in the sidebar and drag to any subfolder, but not to the top
level. As I said, this occurs only sometimes, not always.

Is this intended behaviour or a bug?

Thanks,
Andreas