Fixed name sorting issue

Author: WillAyd

pandas/core/groupby/generic.py

@@ -1455,9 +1455,12 @@ def _insert_inaxis_grouper_inplace(self, result):
 
     def _wrap_aggregated_output(self, output, names=None):
         agg_axis = 0 if self.axis == 1 else 1
-        agg_labels = self._obj_with_exclusions._get_axis(agg_axis)
 
-        output_keys = self._decide_output_index(output, agg_labels)
+        if isinstance(output, dict):
+            output_keys = output.keys()
+        else:
+            agg_labels = self._obj_with_exclusions._get_axis(agg_axis)
+            output_keys = self._decide_output_index(output, agg_labels)
 
         if not self.as_index:
             result = DataFrame(output, columns=output_keys)