Bug 28510 java build path inconsistency [build path]
20021216 select rt.jar in the package explorer open properties it allows you to set the javadoc location but for source attachment you are sent somewhere else it's inconsistent - on the java build path they both look sort of the same (they sit under the same node in the tree)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/LibrariesWorkbookPage.java
public void selectionChanged(TreeListDialogField field) {
			libaryPageSelectionChanged(field);
		}
		
		public void doubleClicked(TreeListDialogField field) {
			libaryPageDoubleClicked(field);
		}
		public Object[] getChildren(TreeListDialogField field, Object element) {
			if (element instanceof CPListElement) {
				return ((CPListElement) element).getChildren(false);
			}
			return EMPTY_ARR;
		}
		public Object getParent(TreeListDialogField field, Object element) {
			if (element instanceof CPListElementAttribute) {
				return ((CPListElementAttribute) element).getParent();
			}
			return null;
		}
		public boolean hasChildren(TreeListDialogField field, Object element) {
			return (element instanceof CPListElement);
		}		
			
		
	
		public void dialogFieldChanged(DialogField field) {
			libaryPageDialogFieldChanged(field);
		}
	}