Problem: Adding new features causes the entire display to refresh
This problem is addressed in ArcGIS 8.1 Service Pack 1. See Related Information section to download this pack.
Creating a new feature invalidates the entire display, this forces ArcMap to refresh the screen.
This is a known issue.
Solution or Workaround
A partial workaround is to zoom in to the area you are editing and shut off layers that are not required to make the edit. This minimizes the impact of the refresh.