Hmm.. Just to get a more complete picture, when Option-clicking a track to select its regions, does it select the regions AND make a duplicate track, or just make a duplicate track INSTEAD of selecting the regions? Does the duplicate track contain the regions, or is it a blank track?
Could you be accidentally Option-RIGHT-clicking? If I do that the contextual menu that pops up has a bunch of new track commands right near the top -- maybe the mouse (or trackpad?) is overly sensitive and is accessing one of the new/duplicate track commands there..? For that matter, Control-click is the same as a right click -- maybe you're accidentally hitting the Control key, or the keyboard has a short and is sending Control instead of/in addition to Option? Does the Option key work properly with other commands in Logic that use it? And if not, do you have another keyboard to test with?
Just off the top of my head, here's a few other things that come to mind as possible additional troubleshooting tests..
- You can try the usual troubleshooting tactics -- restart the computer, test in a fresh empty Logic Project, test with a new User account , etc -- to see if the behavior persists?
- Can you test the same Project in another version of Logic on another computer?
- Maybe one of the "New track..." commands has been assigned a custom key command -- perhaps check the Key Commands window?
- With the Prefs off, what happens if after selecting the Region(s) to be moved, you use the up/down arrow keys to select the destination track instead of clicking on it (to verify it's an Option key issue)?
- Or what happens if you select the destination track in the Mixer window instead of in the Track list (same reason as above)?
I only had 10.4.4 installed for a short while, and I don't recall if I tried this with it.. Of course you could try updating Logic to 10.4.6 -- remember to save the current version by renaming it (or renaming and zipping it) first in case you need to go back..
If you ultimately can't get it to work as advertised, you could always file a bug report with Apple..
https://www.apple.com/feedback/logic-pro.html
Note: that feedback link is just for reporting, it's not a support ticket, so you shouldn't expect a response ..