When checking models after identifying entities, if you drag a box to delete entities, you may also delete the CAD lines on drawings by mistake. To reduce these mis-operations, you can use Lock.

1. In the Drawing Manager, go to the Lock The imported drawings are locked by default.
   
2. To make changes on drawings, you need to click the Lock icon to unlock the drawing first.
   
3. After the changes are completed, if you want to lock the drawing, just click the Lock icon again.