To Change the Display of a Level in All Views in All Models Stored in the Open DGN File

In the Level Display dialog, select Global Display from the Mode option menu.
Select the level.
The display of the selected level changes (on or off) in all views in all models.

This has the same effect as turning on the check mark in the Global column on the Level Manager dialog.

Note: All views have the same levels on or off when Mode is set to Global Display in the Level Display dialog.