FsRtlNotifyVolumeEvent call not propagating?

After dismounting my file system I call FsRtlNotifyVolumeEvent(FileObject,
FSRTL_VOLUME_DISMOUNT). This should notify Windows Explorer that the file
system has dismounted and the focus of the cursor should be moved from my
dismounted drive to another drive. This action occurs so the user won’t see
the error, “CD Drive refers to a location that is unavailable.”

The problem: when entering Standby, the device that I’m mounted on is
disconnected (but I do dismount my file system before entering Standby).
After Resuming, Windows Explorer still has focus on the non-existant drive
and the message, “CD Drive refers to a location that is unavailable” is

Is there something else I should be doing to get Windows Explorer to move
the user focus from my dismounted drive? This occurs on Windows XP SP2 but
not SP1.

Thanks for any insight!