force topic list to use actual displayed list of topics

mapviz_plugins/src/topic_select.cpp

@@ -335,17 +335,19 @@ std::vector<std::string> SelectTopicDialog::filterTopics(
 void SelectTopicDialog::updateDisplayedTopics()
 {
   std::vector<std::string> next_displayed_topics = filterTopics(known_topics_);
-
   // It's a lot more work to keep track of the additions/removals like
   // this compared to resetting the QListWidget's items each time, but
   // it allows Qt to properly track the selection and current items
   // across updates, which results in much less frustration for the user.
 
+  displayed_topics_.clear();
   std::set<std::string> prev_names;
-  for (const auto & displayed_topic : displayed_topics_) {
-    prev_names.insert(displayed_topic);
-  }
 
+  for (int i = 0; i < ui_->topicList->count(); i++)
+  {
+    prev_names.insert(ui_->topicList->item(i)->text().toStdString());
+    displayed_topics_.push_back(ui_->topicList->item(i)->text().toStdString());
+  }
   std::set<std::string> next_names;
   for (const auto & next_displayed_topic : next_displayed_topics) {
     next_names.insert(next_displayed_topic);
@@ -375,6 +377,7 @@ void SelectTopicDialog::updateDisplayedTopics()
   }
 
   // Now we can add the new items.
+
   for (size_t i = 0; i < next_displayed_topics.size(); i++) {
     if (added_names.count(next_displayed_topics[i]) == 0) {
       continue;