public MultiSelectAction getMultiSelectAction() {
        return multiSelectAction;
    }
Give multi-select action for this command. In case it's null command is
executed once without virtual changes in selection ranges. Otherwise
see {@link MultiSelectAction} for details.

@return multi-select action
stroom-core-client-widget/src/main/java/edu/ycp/cs/dh/acegwt/client/ace/AceCommandDescription.java