The patch to implement: Validate properties specified for sorting and grouping in index views. Original patch from martin.v.loewis via: https://hg.python.org/tracker/roundup/rev/439bd3060df2 Applied by John Rouillard with some modification to properly identify if the bad property is a sort or grouping property. Tests added. has an issue with the current code base. Apparently sometime it can be entered without self.classname being defined. As a result the property lookup fails. So guard it by checking for self.classname in a couple of spots and if self.classname is not set just append the property and let the target action sort it out.