Bug 126414 [Commands] handlers: Provide help context ids
For commands and handlers to replace actions, they need to be capable of providing help context identifiers. For an example, see OpenResourceHandler in org.eclipse.ui.ide. This help context id will need to be definable through XML and through code.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/CommandManager.java
definedCategoryIds.add(categoryId);
			} else {
				definedCategoryIds.remove(categoryId);
			}
			if (isListenerAttached()) {
				fireCommandManagerChanged(new CommandManagerEvent(this, null,
						false, false, categoryId, categoryIdAdded, true));
			}
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.commands.ICommandListener#commandChanged(org.eclipse.commands.CommandEvent)
	 */
	public final void commandChanged(final CommandEvent commandEvent) {
		if (commandEvent.isDefinedChanged()) {
			final Command command = commandEvent.getCommand();
			final String commandId = command.getId();
			final boolean commandIdAdded = command.isDefined();
			if (commandIdAdded) {
				definedHandleObjects.add(command);
			} else {
				definedHandleObjects.remove(command);
			}
			if (isListenerAttached()) {
				fireCommandManagerChanged(new CommandManagerEvent(this,
						commandId, commandIdAdded, true, null, false, false));
			}
		}