Comment-Headline is not being updated with the correct comment count, due this would require quite a lot of coding for a very minor mathematical correctness
May breaks other AJAX- or DHTML-Plugins if those are using the same JS-Library. This PlugIn is based on Prototype, so if you have other PlugIns activated using the same library you want to make sure the prototype-script is only loaded once! Sorry for the inconvinience, but it looks like there’s no better solution for this yet.