Thank you kindly, Tiffany for a patch that helps:

Drag copy a prim and the prim that is moved, persists. 
The prim that is created does not survive a restart.

1 files changed, 7 insertions, 0 deletions

diff --git a/OpenSim/Region/Environment/Scenes/InnerScene.cs b/OpenSim/Region/Environment/Scenes/InnerScene.cs
index 65012ad..84de71f 100644
--- a/OpenSim/Region/Environment/Scenes/InnerScene.cs
+++ b/OpenSim/Region/Environment/Scenes/InnerScene.cs
@@ -1417,6 +1417,13 @@ namespace OpenSim.Region.Environment.Scenes
                         Entities.Add(copy.UUID, copy);
                     }
 
+                                        // Since we copy from a source group that is in selected
+                                        // state, but the copy is shown deselected in the viewer,
+                                        // We need to clear the selection flag here, else that
+                                        // prim never gets persisted at all. The client doesn't
+                                        // think it's selected, so it will never send a deselect...
+                                        copy.IsSelected=false;
+
                     m_numPrim++;
 
                     copy.StartScripts();