Bug 123040 [Commands] request: display help topic
I'm going to attach a patch to "command-ify" the opening of help topics. The command takes a parameter which is the href of a help topic. The default handler uses IWorkbenchHelpSystem.displayHelpResource(String) with the href parameter. If no parameter was given, the default handler calls IWorkbenchHelpSystem.displayHelp() instead to simply open the help system. Note that this looks like it should be opened against User Assistance, but the plugins that should be patched (I think) are org.eclipse.ui and org.eclipse.ui.workbench, so I opened against UI.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/ParameterizedCommand.java
* the given command. If the command has no parameters, then this is simply
	 * a parameterized version of that command. If a parameter is optional, both
	 * the included and not included cases are considered.
	 * </p>
	 * <p>
	 * If one of the parameters cannot be loaded due to a
	 * <code>ParameterValuesException</code>, then it is simply ignored.
	 * </p>
	 * 
	 * @param command
	 *            The command for which the parameter combinations should be
	 *            generated; must not be <code>null</code>.
	 * @return A collection of <code>ParameterizedCommand</code> instances
	 *         representing all of the possible combinations. This value is
	 *         never empty and it is never <code>null</code>.
	 * @throws NotDefinedException
	 *             If the command is not defined.
	 */
	public static final Collection generateCombinations(final Command command)
			throws NotDefinedException {
		final IParameter[] parameters = command.getParameters();
		if (parameters == null) {
			return Collections
					.singleton(new ParameterizedCommand(command, null));
		}
		final Collection expansion = expandParameters(0, parameters);
		final Collection combinations = new ArrayList(expansion.size());
		final Iterator expansionItr = expansion.iterator();
		while (expansionItr.hasNext()) {
			final List combination = (List) expansionItr.next();