Bug 114512 [working sets] Package explorer should only allow working sets that have an updater installed
I20051101-0010 The package explorer started to support working sets different than the Java working set. However, the package explorer must ensure that an working set updater is installed otherwise it will end up showing stale/bogus content.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/WorkingSetConfigurationDialog.java
if (editedWorkingSet.getElements().equals(originalWorkingSet.getElements()) == false) {
				editedWorkingSet.setElements(originalWorkingSet.getElements());
			}
		}
	}
	/**
	 * Adds back removed working sets to the working set manager.
	 */
	private void restoreRemovedWorkingSets() {
		IWorkingSetManager manager= PlatformUI.getWorkbench().getWorkingSetManager();
		Iterator iterator= fRemovedWorkingSets.iterator();
		while (iterator.hasNext()) {
			manager.addWorkingSet(((IWorkingSet)iterator.next()));
		}
		iterator= fRemovedMRUWorkingSets.iterator();
		while (iterator.hasNext()) {
			manager.addRecentWorkingSet(((IWorkingSet)iterator.next()));
		}
	}
	/**
	 * Updates the modify buttons' enabled state based on the current seleciton.
	 */
	private void updateButtonAvailability() {
		IStructuredSelection selection= (IStructuredSelection) fTableViewer.getSelection();
		boolean hasSelection= !selection.isEmpty();
		boolean hasSingleSelection= selection.size() == 1;
		fRemoveButton.setEnabled(hasSelection && areAllGlobalWorkingSets(selection));
		fEditButton.setEnabled(hasSingleSelection && ((IWorkingSet)selection.getFirstElement()).isEditable());
		if (fUpButton != null) {
			fUpButton.setEnabled(canMoveUp());