X2 Clip lock issue, help!

I think you're trying to untick the Automation Read check box under the drop-down for Lock. Choose "Off" from the drop-down.

I can reproduce what's in the video, but that's not an issue. I believe there are two or more clips in the range you select by lasso-clicking (right-click dragging). For example, in the screenshot I attached below, there's a very short clip at the beginning of bar 3 (it's too short to notice) and that's why the Start and Length fields in the Clip Properties Inspector both say "(Multi)." And the "Lock Position" and "Lock Data" are both checked although the long clip doesn't have a padlock icon on it. It's because only the short, invisible clip is locked.
 

(Larger image here)

Try the following:
 
1. Click the blank space in the track once (to deselect any selected clip/track).
2. Click the track number on the track strip to select all clips in the track. Make sure the Clip Name, Start and Length fields in the Clip Properties Inspector say "(Multi)."
3. Now, hold down the Ctrl key and click the top half of all clips that are visible in the track. This will deselect those visible clips. The fields in the Clip Properties Inspector should still say "(Multi)" because the invisible clips are still selected.
4. Select "Off" from the Lock drop-down in the Clip Properties Inspector. This will unlock all locked clips that are selected.
5. Hit the Delete Key to delete all the invisible clips.