It seems that ListGridField canSort: false stopped working (partially) in version SmartClient_v100p_2014-12-30_LGPL.
canSort: false removes sort options from the menu of the field's header but still lets the user click to sort (although doesn't make the field "Selected" - just adds an arrow)
canSort: false removes sort options from the menu of the field's header but still lets the user click to sort (although doesn't make the field "Selected" - just adds an arrow)