Logic Pro 9 Why does one region refuse to copy to other track?

Hi all, I have a problem with one region that refuses to be copied to the track below it-which is empty, any ideas? Copy/Paste won't, dragging with alt won't. Am I forgetting a rule about track types?
Logic allows you to put the "wrong" kind of region on track (say, an audio region on a MIDI track, which obviously then wouldn't be heard).

.... unless there is something new that has changed.

What happens if drag (without copy) the region to the destination track?


Is either the track or the region locked in any way? (either track protect, or region locked to smpte position)
Thank you all for your help. The tracks are instrument tracks, nothing is hidden or soloed or locked or muted. I copied the track to a new version of that song and it can be moved-I am assuming the standard corrupted song file was the issue. I see many reports on all the Logic forums about things not working some times[and this song was started in Logic EXpress 7-I remember someone advising opening pre Logic 9 songs first in Logic 8 then save the song and it will open in Logic 9 Logic and it could just be that.
Again, Thanks to you all for the help