diff --git a/src/tools/uic/cpp/cppwriteincludes.cpp b/src/tools/uic/cpp/cppwriteincludes.cpp
index 74546bb01d..0ba49627c0 100644
--- a/src/tools/uic/cpp/cppwriteincludes.cpp
+++ b/src/tools/uic/cpp/cppwriteincludes.cpp
@@ -214,14 +214,14 @@ void WriteIncludes::add(const QString &className, bool determineHeader, const QS
     m_knownClasses.insert(className);
 
     const CustomWidgetsInfo *cwi = m_uic->customWidgetsInfo();
-    if (cwi->extends(className, QLatin1String("QTreeView"))
-               || cwi->extends(className, QLatin1String("QTreeWidget"))
-               || cwi->extends(className, QLatin1String("QTableView"))
-               || cwi->extends(className, QLatin1String("QTableWidget"))) {
+    static const QStringList treeViewsWithHeaders = {
+        QLatin1String("QTreeView"), QLatin1String("QTreeWidget"),
+        QLatin1String("QTableView"), QLatin1String("QTableWidget")
+    };
+    if (cwi->extendsOneOf(className, treeViewsWithHeaders))
         add(QLatin1String("QHeaderView"));
-    }
 
-    if (!m_laidOut && m_uic->customWidgetsInfo()->extends(className, QLatin1String("QToolBox")))
+    if (!m_laidOut && cwi->extends(className, QLatin1String("QToolBox")))
         add(QLatin1String("QLayout")); // spacing property of QToolBox)
 
     if (className == QLatin1String("Line")) { // ### hmm, deprecate me!
diff --git a/src/tools/uic/cpp/cppwriteinitialization.cpp b/src/tools/uic/cpp/cppwriteinitialization.cpp
index 9db20a5395..dbe4860d7e 100644
--- a/src/tools/uic/cpp/cppwriteinitialization.cpp
+++ b/src/tools/uic/cpp/cppwriteinitialization.cpp
@@ -608,18 +608,23 @@ void WriteInitialization::acceptWidget(DomWidget *node)
     if (m_uic->isContainer(parentClass))
         parentWidget.clear();
 
-    if (m_widgetChain.size() != 1)
-        m_output << m_indent << varName << " = new " << m_uic->customWidgetsInfo()->realClassName(className) << '(' << parentWidget << ");\n";
+    const auto *cwi = m_uic->customWidgetsInfo();
+
+    if (m_widgetChain.size() != 1) {
+        m_output << m_indent << varName << " = new " << cwi->realClassName(className)
+            << '(' << parentWidget << ");\n";
+    }
 
     parentWidget = savedParentWidget;
 
-    if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QComboBox"))) {
+
+    if (cwi->extends(className, QLatin1String("QComboBox"))) {
         initializeComboBox(node);
-    } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QListWidget"))) {
+    } else if (cwi->extends(className, QLatin1String("QListWidget"))) {
         initializeListWidget(node);
-    } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTreeWidget"))) {
+    } else if (cwi->extends(className, QLatin1String("QTreeWidget"))) {
         initializeTreeWidget(node);
-    } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTableWidget"))) {
+    } else if (cwi->extends(className, QLatin1String("QTableWidget"))) {
         initializeTableWidget(node);
     }
 
@@ -629,7 +634,7 @@ void WriteInitialization::acceptWidget(DomWidget *node)
     writeProperties(varName, className, node->elementProperty());
 
     if (!parentWidget.isEmpty()
-        && m_uic->customWidgetsInfo()->extends(className, QLatin1String("QMenu"))) {
+        && cwi->extends(className, QLatin1String("QMenu"))) {
         initializeMenu(node, parentWidget);
     }
 
@@ -657,10 +662,10 @@ void WriteInitialization::acceptWidget(DomWidget *node)
 
     const QString pageDefaultString = QLatin1String("Page");
 
-    if (m_uic->customWidgetsInfo()->extends(parentClass, QLatin1String("QMainWindow"))) {
-        if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QMenuBar"))) {
+    if (cwi->extends(parentClass, QLatin1String("QMainWindow"))) {
+        if (cwi->extends(className, QLatin1String("QMenuBar"))) {
             m_output << m_indent << parentWidget << "->setMenuBar(" << varName <<");\n";
-        } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QToolBar"))) {
+        } else if (cwi->extends(className, QLatin1String("QToolBar"))) {
             m_output << m_indent << parentWidget << "->addToolBar("
                      << toolBarAreaStringFromDOMAttributes(attributes) << varName << ");\n";
 
@@ -670,7 +675,7 @@ void WriteInitialization::acceptWidget(DomWidget *node)
                 }
             }
 
-        } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QDockWidget"))) {
+        } else if (cwi->extends(className, QLatin1String("QDockWidget"))) {
             m_output << m_indent << parentWidget << "->addDockWidget(";
             if (DomProperty *pstyle = attributes.value(QLatin1String("dockWidgetArea")))
                 m_output << "Qt::" << language::dockWidgetArea(pstyle->elementNumber()) << ", ";
@@ -683,9 +688,9 @@ void WriteInitialization::acceptWidget(DomWidget *node)
     }
 
     // Check for addPageMethod of a custom plugin first
-    QString addPageMethod = m_uic->customWidgetsInfo()->customWidgetAddPageMethod(parentClass);
+    QString addPageMethod = cwi->customWidgetAddPageMethod(parentClass);
     if (addPageMethod.isEmpty())
-        addPageMethod = m_uic->customWidgetsInfo()->simpleContainerAddPageMethod(parentClass);
+        addPageMethod = cwi->simpleContainerAddPageMethod(parentClass);
     if (!addPageMethod.isEmpty()) {
         m_output << m_indent << parentWidget << "->" << addPageMethod << '(' << varName << ");\n";
     } else if (m_uic->customWidgetsInfo()->extends(parentClass, QLatin1String("QWizard"))) {
@@ -753,8 +758,14 @@ void WriteInitialization::acceptWidget(DomWidget *node)
         QLatin1String("stretchLastSection"),
     };
 
-    if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTreeView"))
-               || m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTreeWidget"))) {
+    static const QStringList trees = {
+        QLatin1String("QTreeView"), QLatin1String("QTreeWidget")
+    };
+    static const QStringList tables = {
+        QLatin1String("QTableView"), QLatin1String("QTableWidget")
+    };
+
+    if (cwi->extendsOneOf(className, trees)) {
         DomPropertyList headerProperties;
         for (auto realPropertyName : realPropertyNames) {
             const QString fakePropertyName = QLatin1String("header")
@@ -767,9 +778,7 @@ void WriteInitialization::acceptWidget(DomWidget *node)
         writeProperties(varName + QLatin1String("->header()"), QLatin1String("QHeaderView"),
                         headerProperties, WritePropertyIgnoreObjectName);
 
-    } else if (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTableView"))
-               || m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTableWidget"))) {
-
+    } else if (cwi->extendsOneOf(className, tables)) {
         static const QLatin1String headerPrefixes[] = {
             QLatin1String("horizontalHeader"),
             QLatin1String("verticalHeader"),
@@ -1166,11 +1175,12 @@ void WriteInitialization::writeProperties(const QString &varName,
                        << p->elementNumber() << ");\n";
             continue;
         }
+        static const QStringList currentIndexWidgets = {
+            QLatin1String("QComboBox"), QLatin1String("QStackedWidget"),
+            QLatin1String("QTabWidget"), QLatin1String("QToolBox")
+        };
         if (propertyName == QLatin1String("currentIndex") // set currentIndex later
-            && (m_uic->customWidgetsInfo()->extends(className, QLatin1String("QComboBox"))
-                || m_uic->customWidgetsInfo()->extends(className, QLatin1String("QStackedWidget"))
-                || m_uic->customWidgetsInfo()->extends(className, QLatin1String("QTabWidget"))
-                || m_uic->customWidgetsInfo()->extends(className, QLatin1String("QToolBox")))) {
+            && (m_uic->customWidgetsInfo()->extendsOneOf(className, currentIndexWidgets))) {
             m_delayedOut << m_indent << varName << "->setCurrentIndex("
                        << p->elementNumber() << ");\n";
             continue;
diff --git a/src/tools/uic/customwidgetsinfo.cpp b/src/tools/uic/customwidgetsinfo.cpp
index 4afdf74d08..d6a409152b 100644
--- a/src/tools/uic/customwidgetsinfo.cpp
+++ b/src/tools/uic/customwidgetsinfo.cpp
@@ -75,6 +75,24 @@ bool CustomWidgetsInfo::extends(const QString &classNameIn, QLatin1String baseCl
     return false;
 }
 
+bool CustomWidgetsInfo::extendsOneOf(const QString &classNameIn,
+                                     const QStringList &baseClassNames) const
+{
+    if (baseClassNames.contains(classNameIn))
+        return true;
+
+    QString className = classNameIn;
+    while (const DomCustomWidget *c = customWidget(className)) {
+        const QString extends = c->elementExtends();
+        if (className == extends) // Faulty legacy custom widget entries exist.
+            return false;
+        if (baseClassNames.contains(extends))
+            return true;
+        className = extends;
+    }
+    return false;
+}
+
 bool CustomWidgetsInfo::isCustomWidgetContainer(const QString &className) const
 {
     if (const DomCustomWidget *dcw = m_customWidgets.value(className, 0))
diff --git a/src/tools/uic/customwidgetsinfo.h b/src/tools/uic/customwidgetsinfo.h
index a4278b1aca..8a10999027 100644
--- a/src/tools/uic/customwidgetsinfo.h
+++ b/src/tools/uic/customwidgetsinfo.h
@@ -57,6 +57,7 @@ public:
     QString realClassName(const QString &className) const;
 
     bool extends(const QString &className, QLatin1String baseClassName) const;
+    bool extendsOneOf(const QString &className, const QStringList &baseClassNames) const;
 
     bool isCustomWidgetContainer(const QString &className) const;
 
diff --git a/src/tools/uic/uic.cpp b/src/tools/uic/uic.cpp
index b426d33e5c..225dc6aeb2 100644
--- a/src/tools/uic/uic.cpp
+++ b/src/tools/uic/uic.cpp
@@ -245,28 +245,32 @@ void Uic::writeHeaderProtectionEnd()
 
 bool Uic::isButton(const QString &className) const
 {
-    return customWidgetsInfo()->extends(className, QLatin1String("QRadioButton"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QToolButton"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QCheckBox"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QPushButton"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QCommandLinkButton"));
+    static const QStringList buttons = {
+        QLatin1String("QRadioButton"), QLatin1String("QToolButton"),
+        QLatin1String("QCheckBox"), QLatin1String("QPushButton"),
+        QLatin1String("QCommandLinkButton")
+    };
+    return customWidgetsInfo()->extendsOneOf(className, buttons);
 }
 
 bool Uic::isContainer(const QString &className) const
 {
-    return customWidgetsInfo()->extends(className, QLatin1String("QStackedWidget"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QToolBox"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QTabWidget"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QScrollArea"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QMdiArea"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QWizard"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QDockWidget"));
+    static const QStringList containers = {
+        QLatin1String("QStackedWidget"), QLatin1String("QToolBox"),
+        QLatin1String("QTabWidget"), QLatin1String("QScrollArea"),
+        QLatin1String("QMdiArea"), QLatin1String("QWizard"),
+        QLatin1String("QDockWidget")
+    };
+
+    return customWidgetsInfo()->extendsOneOf(className, containers);
 }
 
 bool Uic::isMenu(const QString &className) const
 {
-    return customWidgetsInfo()->extends(className, QLatin1String("QMenu"))
-        || customWidgetsInfo()->extends(className, QLatin1String("QPopupMenu"));
+    static const QStringList menus = {
+        QLatin1String("QMenu"), QLatin1String("QPopupMenu")
+    };
+    return customWidgetsInfo()->extendsOneOf(className, menus);
 }
 
 QT_END_NAMESPACE