message: Fix performance counters without a category
  In the performance counter selection dialog, show counters without a category
  at root of tree, rather than as children of a nameless "" category.
diff: @@ -303,6 +303,13 @@ void PerformanceCounterSelection::SetCounters(const QVector<CounterDescription>
  RDTreeWidgetItem *categoryItem = NULL;
  + if(desc.category.empty())
  + {
  + // Show uncategorized counters at the root level
  + categoryItem = currentRoot;
  + }
  + else
  + {
  const rdcstr category = desc.category;
  auto categoryIterator = categories.find(category);
  @@ -321,6 +328,7 @@ void PerformanceCounterSelection::SetCounters(const QVector<CounterDescription>
  {
  categoryItem = categoryIterator.value();
  }
  + }
  RDTreeWidgetItem *counterItem = new RDTreeWidgetItem();
  counterItem->setText(0, desc.name);
  