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/SourceContainerWorkbookPage.java
fFoldersList.refresh();
				fClassPathList.dialogFieldChanged(); 
			}
		} else if (key.equals(CPListElement.EXCLUSION)) {
			CPListElement selElement= (CPListElement) elem.getParent();
			ExclusionPatternDialog dialog= new ExclusionPatternDialog(getShell(), selElement);
			if (dialog.open() == OutputLocationDialog.OK) {
				selElement.setAttribute(CPListElement.EXCLUSION, dialog.getExclusionPattern());
				fFoldersList.refresh();
				fClassPathList.dialogFieldChanged(); 
			}		
		}
	}
	
	protected void sourcePageSelectionChanged(DialogField field) {
		List selected= fFoldersList.getSelectedElements();
		fFoldersList.enableButton(IDX_EDIT, canEdit(selected));
	}
	
	private boolean canEdit(List selElements) {
		if (selElements.size() != 1) {
			return false;
		}
		Object elem= selElements.get(0);
		if (fFoldersList.getIndexOfElement(elem) != -1) {
			return true;
		}
		if (elem instanceof CPListElementAttribute) {
			return true;
		}