A workaround has been added to Clearlooks and other engines like Murrine to support programs that draw fake Gtk+ widgets (Firefox). This workaround provides a "transparent-bg-hint" that can be set to prevent the background from being drawn on entry and progress bar widgets. The intent is to fix a cosmetic defect that manifests itself as an unwanted rectangle surrounding these widgets. I've attached a patch that does a similar thing in Nodoka.