Bug 166015 Refactor designer actions to eclipse command framework
Eclipse command framework provide a more explicit way to manage UI actions contributions, we can take it's advantage to make our actions code more clean and maintainable.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dnd/InsertInLayoutUtil.java
.hasNext( ) )
						|| insertObj.getElementHandle( ).equals( dataSet );
			}
		}
		return false;
	}
	private static boolean isMasterPageHeaderOrFooter( Object obj )
	{
		if ( !( obj instanceof SlotHandle ) )
		{
			return false;
		}
		if ( ((SlotHandle) obj).getElementHandle( ) instanceof MasterPageHandle )
		{
			return true;
		}
		return false;
	}
	/**
	 * Validates drop target from scalar parameter in data view.
	 * 
	 * @return validate result
	 */
	protected static boolean handleValidateParameter( EditPart target )
	{
		return handleValidateParameterDropContainer( target )
				&& DNDUtil.handleValidateTargetCanContainType( target.getModel( ),
						ReportDesignConstants.DATA_ITEM );
	}
	/**