QtCharts treats <empty> as rich text

analyzer/model/categoryaggregationmodel.cpp

@@ -97,7 +97,7 @@ QVariant CategoryAggregationModel::headerData(int section, Qt::Orientation orien
         if (role == Qt::DisplayRole) {
             const auto cat = m_categories.at(section - 1);
             if (cat.isEmpty())
-                return tr("<empty>");
+                return tr("[empty]");
             return cat;
         }
     }

analyzer/model/ratiosetaggregationmodel.cpp

@@ -93,7 +93,7 @@ QVariant RatioSetAggregationModel::headerData(int section, Qt::Orientation orien
         if (role == Qt::DisplayRole) {
             const auto cat = m_categories.at(section - 1);
             if (cat.isEmpty())
-                return tr("<empty>");
+                return tr("[empty]");
             return cat;
         }
     }

tests/auto/categoryaggregationmodeltest.cpp

@@ -95,7 +95,7 @@ private slots:
         srcModel.setSamples(samples);
 
         QCOMPARE(model.columnCount(), 4);
-        QCOMPARE(model.headerData(1, Qt::Horizontal, Qt::DisplayRole).toString(), QLatin1String("<empty>"));
+        QCOMPARE(model.headerData(1, Qt::Horizontal, Qt::DisplayRole).toString(), QLatin1String("[empty]"));
         QCOMPARE(model.headerData(2, Qt::Horizontal, Qt::DisplayRole).toString(), QLatin1String("1.0"));
         QCOMPARE(model.headerData(3, Qt::Horizontal, Qt::DisplayRole).toString(), QLatin1String("1.9.84"));