diff --git a/core/app.py b/core/app.py
index db15fcfe..20e31a3b 100644
--- a/core/app.py
+++ b/core/app.py
@@ -770,6 +770,8 @@ class DupeGuru(Broadcaster):
         for group in self.results.groups:
             if group.prioritize(key_func=sort_key):
                 count += 1
+        if count:
+            self.results.refresh_required = True
         self._results_changed()
         msg = tr("{} duplicate groups were changed by the re-prioritization.").format(
             count
diff --git a/core/results.py b/core/results.py
index 68923548..14c27880 100644
--- a/core/results.py
+++ b/core/results.py
@@ -52,6 +52,7 @@ class Results(Markable):
         self.app = app
         self.problems = []  # (dupe, error_msg)
         self.is_modified = False
+        self.refresh_required = False
 
     def _did_mark(self, dupe):
         self.__marked_size += dupe.size
@@ -94,21 +95,23 @@ class Results(Markable):
 
     # ---Private
     def __get_dupe_list(self):
-        self.__dupes = flatten(group.dupes for group in self.groups)
-        if None in self.__dupes:
-            # This is debug logging to try to figure out #44
-            logging.warning(
-                "There is a None value in the Results' dupe list. dupes: %r groups: %r",
-                self.__dupes,
-                self.groups,
-            )
-        if self.__filtered_dupes:
-            self.__dupes = [
-                dupe for dupe in self.__dupes if dupe in self.__filtered_dupes
-            ]
-        sd = self.__dupes_sort_descriptor
-        if sd:
-            self.sort_dupes(sd[0], sd[1], sd[2])
+        if self.__dupes is None or self.refresh_required:
+            self.__dupes = flatten(group.dupes for group in self.groups)
+            self.refresh_required = False
+            if None in self.__dupes:
+                # This is debug logging to try to figure out #44
+                logging.warning(
+                    "There is a None value in the Results' dupe list. dupes: %r groups: %r",
+                    self.__dupes,
+                    self.groups,
+                )
+            if self.__filtered_dupes:
+                self.__dupes = [
+                    dupe for dupe in self.__dupes if dupe in self.__filtered_dupes
+                ]
+            sd = self.__dupes_sort_descriptor
+            if sd:
+                self.sort_dupes(sd[0], sd[1], sd[2])
         return self.__dupes
 
     def __get_groups(self):