Update underlying data field when related object is updated.

If the selected Library Document is out-of-range throw a specific error
Don't fail if the user clicks on open space in the BookMark list
Added property to provide a right margin (RTBMargin) between the RichTextBox and the StepItem

PROMS/VEPROMS.CSLA.Library/Generated/Transition.cs

@@ -136,6 +136,7 @@ namespace VEPROMS.CSLA.Library
 				if (_MyContent != value)
 				{
 					_MyContent = value;
+					_FromID = value.ContentID;// Update underlying data field
 					PropertyHasChanged();
 				}
 			}
@@ -171,6 +172,7 @@ namespace VEPROMS.CSLA.Library
 				if (_MyItemToID != value)
 				{
 					_MyItemToID = value;
+					_ToID = value.ItemID;// Update underlying data field
 					PropertyHasChanged();
 				}
 			}
@@ -203,6 +205,7 @@ namespace VEPROMS.CSLA.Library
 				if (_MyItemRangeID != value)
 				{
 					_MyItemRangeID = value;
+					_RangeID = value.ItemID;// Update underlying data field
 					PropertyHasChanged();
 				}
 			}