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
while (combination.remove(null)) {
				
			}
			if (combination.isEmpty()) {
				combinations.add(new ParameterizedCommand(command, null));
			} else {
				final Parameterization[] parameterizations = (Parameterization[]) combination
						.toArray(new Parameterization[combination.size()]);
				combinations.add(new ParameterizedCommand(command,
						parameterizations));
			}
		}
		return combinations;
	}
	/**
	 * The base command which is being parameterized. This value is never
	 * <code>null</code>.
	 */
	private final Command command;
	/**
	 * The hash code for this object. This value is computed lazily, and marked
	 * as invalid when one of the values on which it is based changes.
	 */
	private transient int hashCode = HASH_CODE_NOT_COMPUTED;
	/**
	 * This is an array of parameterization defined for this command. This value
	 * may be <code>null</code> if the command has no parameters.
	 */
	private final Parameterization[] parameterizations;
	/**