Please add DropDownTree and/or TreeView as single- and multi-value parameter editors to accommodate Hierarchical data. It would be nice to have them out-of-the-box when available values come from a hierarchical/self-referencing table(s), but I would be happy if they could be integrated as Custom Parameter Editors. I was able to render and populate the dropdowntree with checkboxes, pass the correct selected values, but the 'Preview' button would never enable upon selection. Also, the dropdowntree's AutoClose(false) was not recognized. I know this can be achieved outside of the report viewer, but sometimes that method disrupts the layout and flow of the reporting view.