Deleting All Levels

I have been telling people for years that Revit needs at least one level to function. As proof, if you only have one level you'll find that Revit won't let you delete it, the last one. The Delete button is disabled and it ignores you if you tap the Delete key.

I find it disturbing and interesting that it IS possible to delete all the levels as long as you select all of them and delete them together, at the same time. No complaint from Revit at all.

That seems like more like a bug than a feature to me. It works this way as far back as v2013, as far back as I've tested it.

What if you've done that, deleted all of them? You'll probably be a bit disappointed at the condition of what was your model...but just open an elevation view and create a new level(s).

Enable 2D Setting for Multiple Grid Lines

There are times when we'd like to alter the 2D (view specific) position of Grids. When you select a Grid you can click the 3D icon to toggle it to 2D. That's a one-at-a-time affair though. If you have many grids you won't look forward to doing that.

When a Grid crosses a crop boundary in a view (when the crop boundary is enabled) it switches from 3D to 2D automatically. If you want to enable the 2D setting for all the vertical grids at once turn on the view's crop boundary and make sure it crosses your grids.

Now you can adjust all the Grids end point position together just like they do automatically for the 3D setting. It will work for levels too. If you don't want the crop region long term you can just disable it afterward. The Grids or Levels will retain their alteration until (if) you elect to use the Reset to 3D Extents (right click context menu option).