After modifying a 2D datum to the desired extent, you can choose to have the datum look the same in similar views.
Video: Propagate the Extents of Datums
You can use Propagate Extents to accomplish this.
To propagate 2D datum extents
There is no permanent connection between the look of the datum in multiple views. If you modify the datum again, you must use Propagate Extents again. Propagate Extents does not affect Model (3D) extents and does not propagate datum offsets.