Bug 41491 Add constructors from fields issues
200300813 a. add visibility buttons like 'Add constructor from super class'
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/AddUnimplementedConstructorsAction.java
if (type == null) {
				MessageDialog.openInformation(getShell(), getDialogTitle(), ActionMessages.getString("AddUnimplementedConstructorsAction.not_applicable")); 
				return;
			}		
			
			IEditorPart editor= EditorUtility.openInEditor(type);
			type= (IType)EditorUtility.getWorkingCopy(type);
			
			if (type == null) {
				MessageDialog.openError(shell, getDialogTitle(), ActionMessages.getString("AddUnimplementedConstructorsAction.error.type_removed_in_editor")); 
				return;
			}
			
			run(shell, type, editor, false);
		} catch (CoreException e) {
			ExceptionHandler.handle(e, shell, getDialogTitle(), null);
		}			
	}
	
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	protected void selectionChanged(ITextSelection selection) {
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	public void run(ITextSelection selection) {