#666 Unable detach encrypted volume using GUI

[im2009]

I use FreeNAS 0.7RC1;
When I try detach encrypted volume (menu item Disks|Encryption|Tools) messadge that I see "Command output: Device is mounted, umount it first before detaching. ".
But that volume not mounted (I unmount filesystem using GUI and check mount output).
At the same time typed via shell "geli detach" work without errors.

Thanks!