Bug 8595 'Open super implementation' should be disabled
In the Outline view, there seems to be a new menu item 'Open super implementation', and a corresponding decoration on methods to indicate thet they have a super implementation. The UI already knows if the method has a super implementation, so it should disable the menu item when there is no super implementation to open to. Currently it just does nothing if you select a method with no super implementation. (Tested against 20020125 build)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/OpenSuperImplementationAction.java
if (!declaringType.exists()) {
					return;
				}
			}
			ITypeHierarchy hierarchy= declaringType.newSupertypeHierarchy(null);
			IMethod impl= JavaModelUtil.findMethodImplementationInHierarchy(hierarchy, declaringType, method.getElementName(), method.getParameterTypes(), method.isConstructor());
			if (impl == null) {
				
				impl= JavaModelUtil.findMethodDeclarationInHierarchy(hierarchy, declaringType, method.getElementName(), method.getParameterTypes(), method.isConstructor());
			}
			if (impl != null) {
				OpenActionUtil.open(impl);
			}
		} catch (CoreException e) {
			JavaPlugin.log(e);
			String message= ActionMessages.getString("OpenSuperImplementationAction.error.message"); 
			ErrorDialog.openError(getShell(), getDialogTitle(), message, e.getStatus());
		}
	}
	
	private IMethod getMethod(IStructuredSelection selection) {
		if (selection.size() != 1)
			return null;
		Object element= selection.getFirstElement();
		return checkMethod(element);
	}
	
	private IMethod getMethod(ITextSelection selection) {
		return checkMethod(elementAtOffset());
	}