I spent the last hour beating my deciding on which way to destroy my computer, as I battled why my Telerik RadGrid was failing to show the filter data set from my EntityDataSource. (Yes, lazy using these visual controls, but for reports they work well and easy)
Turns out, I had Filtering ON on the data grid. Apparently that disregards the WHERE filter on the data source. Well, that’s a pile of crap.
Anyway, turn off grid filtering or provide your data some other way to the data grid.
Hopefully this saves you time.