Move "From Cursor" operator which sets dupli group offset to own operator

Previously it used to use cursor location from time when panel was drawn,
which in some cases lead to using previous cursor location instead of current.

release/scripts/startup/bl_operators/object.py

@@ -691,3 +691,29 @@ class TransformsToDeltasAnim(Operator):
         context.scene.frame_set(context.scene.frame_current)
 
         return {'FINISHED'}
+
+
+class DupliOffsetFromCursor(Operator):
+    '''Set offset used for DupliGroup based on cursor position'''
+    bl_idname = "object.dupli_offset_from_cursor"
+    bl_label = "Set Offset From Cursor"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    group = IntProperty(
+            name="Group",
+            description="Group index to set offset for",
+            default=0,
+            )
+
+    @classmethod
+    def poll(cls, context):
+        return  context.active_object is not None
+
+    def execute(self, context):
+        scene = context.scene
+        ob = context.active_object
+        group = self.group
+
+        ob.users_group[group].dupli_offset = scene.cursor_location
+
+        return {'FINISHED'}

release/scripts/startup/bl_ui/properties_object.py

@@ -162,7 +162,6 @@ class OBJECT_PT_groups(ObjectButtonsPanel, Panel):
 
         # XXX, this is bad practice, yes, I wrote it :( - campbell
         index = 0
-        value = str(tuple(context.scene.cursor_location))
         for group in bpy.data.groups:
             if ob.name in group.objects:
                 col = layout.column(align=True)
@@ -181,9 +180,8 @@ class OBJECT_PT_groups(ObjectButtonsPanel, Panel):
                 col = split.column()
                 col.prop(group, "dupli_offset", text="")
 
-                props = col.operator("wm.context_set_value", text="From Cursor")
-                props.data_path = "object.users_group[%d].dupli_offset" % index
-                props.value = value
+                props = col.operator("object.dupli_offset_from_cursor", text="From Cursor")
+                props.index = index
                 index += 1