I am afraid currently the Kendo UI PanelBar does not support multiple selection, however such idea sounds good and you could share it as a feature request at our UserVoice page. This way the community would be able to vote and comment it and if this suggestion turns out to be popular, we will consider its implementation. Thank you in advance.
the Telerik team
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI now!