I also noticed that if I select a group of clips and try to drag (or drag-copy), as soon as I move the mouse, all clips are deselected except the one under the mouse cursor.

I'm really scratching my head here........

What happens if you switch snap off? Still the same?

Same exact behavior.

I'm sorry but I haven't got a clue. A few more questions though...

Is it affecting MIDI clips, audio clips, both?
What about newly created clips?
Will they cut and paste?
What about moving a clip with the event inspector? (Select a clip and the enter a new start time in the event inspector's "Time" field.

I'm begining to wonder if your install has become corrupt in some way. Is the rest of the program working as expected?

Perhaps a fresh brain will drop in on this thread with some more ideas or something I haven't thought of. Where are you Bob Bone?

Is it affecting MIDI clips, audio clips, both? 
It is affecting both.



What about newly created clips? 

I tried that and it fails when creating a new clip on the same track. I also added a new synth track and same behavior.




Will they cut and paste? 


Yes, copy/paste and cut/paste works.



What about moving a clip with the event inspector?


This works too.


Thanks a lot for your help.

Robert

No worries, I hate to be beaten but I'm close to conceding defeat. I'm beginning to wonder whether a call to tech support might be needed.

I really can't think of any setting that would cause that other than the stuff you've already checked.

Have you tried changing tools to say the move tool (F7) and see if that makes a difference?

Yes, I tried the Move tool and it fails to drag too. I'll call tech support tomorrow. Thanks again for your help.

No worries. If you ever get it sorted post up and let us know the solution so I can file that one into my memory bank for future reference.

It's certainly very bizarre but may turn out to be something really obvious that neither of us have thought of.

After restarting the system (Windows 7 64) drag and drag copy now work. 

I've had similar weird issues with the now time, zooming and just what you described a few moments ago...