When placing several assets in your scene properly, specially if you need them to be one inside each other, you have the option of locking and unlocking them (only in version V0.5.1).
To lock an asset you must be in Edit mode, with no panel open (check that you have the Mode bubbles on your Right controller). When you aim at any asset the Lock/Unlock option appears on your A button. Simply press while aiming at your asset to lock it. Press again to unlock it.