classes.updates: Keep redo, if ignore_history set

If an update isn't pushed onto the undo stack (ignore_history=True),
there's no reason to clear the redo list.

src/classes/updates.py

@@ -306,19 +306,19 @@ def insert(self, key, values):
         """ Insert a new UpdateAction into the UpdateManager (this action will then be distributed to all listeners) """
 
         self.last_action = UpdateAction('insert', key, values)
-        self.redoHistory.clear()
         if not self.ignore_history:
+            self.redoHistory.clear()
             self.actionHistory.append(self.last_action)
         self.dispatch_action(self.last_action)
 
     def update(self, key, values, partial_update=False):
         """ Update the UpdateManager with an UpdateAction (this action will then be distributed to all listeners) """
 
         self.last_action = UpdateAction('update', key, values, partial_update)
-        if self.last_action.key and self.last_action.key[0] != "history":
-            # Clear redo history for any update except a "history" update
-            self.redoHistory.clear()
         if not self.ignore_history:
+            if self.last_action.key and self.last_action.key[0] != "history":
+                # Clear redo history for any update except a "history" update
+                self.redoHistory.clear()
             self.actionHistory.append(self.last_action)
         self.dispatch_action(self.last_action)
 
@@ -333,8 +333,8 @@ def delete(self, key):
         """ Delete an item from the UpdateManager with an UpdateAction (this action will then be distributed to all listeners) """
 
         self.last_action = UpdateAction('delete', key)
-        self.redoHistory.clear()
         if not self.ignore_history:
+            self.redoHistory.clear()
             self.actionHistory.append(self.last_action)
         self.dispatch_action(self.last_action)