Revit 2011 Level and Grid Visibility in Sections

Resizing datum extent controls:  Sometimes we don't want to see gridlines or level lines going all the way across a view.  The tendency is to just grab an endpoint and drag it.

Problem:  The grid bubble or level marker will often disappear mysteriously from other views.  This is because of a default setting to change the actual 3D extent of the datum plane in all views, not just the current view.  Turns out it's not really a "problem", it's a "feature".

Solution:  Notice that there is a control titled 3D that displays at the ends of the datum. With the 3D designation, the datum is in Model Extent mode.  Click it to switch to 2D mode, see example images below.

Before: Model extent mode

After:  View-specific mode

 
Clicking the 3D control changes to display 2D, and the control changes from an open circle to a filled circle. This means the datum is in view-specific mode. If you resize the datum, the change occurs in that view only.

Clicking again toggles back to 3D mode.