OK, so how are you supposed to unlock an object if it's not selectable once you've locked it...
Edit > Group > Unlock unlocks all locked objects which is usually not a desirable action - any thoughts?
Here's a solution, that seems to work, but only on one object (or group) at a time. I don't know why this works - I was just trying stuff out of desperation! I'm running TurboCAD Mac 8.0.8, build (1167)
1) Hold down the command key, and click a locked object. Handles will appear.
2) From the menu bar, select Edit/Group/Unlock.
3) The Edit menu header will stay highlighted (blue for me), appearing locked up.
4) Click on the object again. Highlighted disappears. Now, the object is selectable! If it was locked as part of a group, the whole group is selectable.