When you create a new Detail Drawing or Worksheet – you will often see a dashed line boundary appearing. This shows the zone that was initially highlighted in the creation of the document… and the first thing most people do is delete it! However, the next time you rebuild the view, it will come back, and keep coming back!
To prevent this, you can uncheck the option in the Work Environment that will prevent the boundary from being created in the first place. To deactivate this option, go to Options> Work Environment> More Options:
Make sure Create Detail / Worksheet Boundary in Details / Worksheet Window is not checked as highlighted above. And be sure to update your User Preference Scheme! In the BIM6x Work Environment, this option is deactivated as default. _