diff --git a/src/plugins/cppeditor/cppcompletion_test.cpp b/src/plugins/cppeditor/cppcompletion_test.cpp
index 738eaa08367..cf8b163ab4e 100644
--- a/src/plugins/cppeditor/cppcompletion_test.cpp
+++ b/src/plugins/cppeditor/cppcompletion_test.cpp
@@ -150,7 +150,7 @@ public:
             return true;
         return ::CppEditor::Tests::waitForSignalOrTimeout(
             cppEditor->textDocument()->syntaxHighlighterRunner(),
-            &BaseSyntaxHighlighterRunner::highlightingFinished,
+            &SyntaxHighlighterRunner::highlightingFinished,
             5000);
     }
 
diff --git a/src/plugins/cppeditor/cppeditordocument.cpp b/src/plugins/cppeditor/cppeditordocument.cpp
index d1297b1dd38..badd02b751b 100644
--- a/src/plugins/cppeditor/cppeditordocument.cpp
+++ b/src/plugins/cppeditor/cppeditordocument.cpp
@@ -164,7 +164,7 @@ QByteArray CppEditorDocument::contentsText() const
 
 void CppEditorDocument::applyFontSettings()
 {
-    if (TextEditor::BaseSyntaxHighlighterRunner *highlighter = syntaxHighlighterRunner())
+    if (TextEditor::SyntaxHighlighterRunner *highlighter = syntaxHighlighterRunner())
         highlighter->clearAllExtraFormats(); // Clear all additional formats since they may have changed
     TextDocument::applyFontSettings(); // rehighlights and updates additional formats
     if (m_processor)
@@ -408,7 +408,7 @@ BaseEditorDocumentProcessor *CppEditorDocument::processor()
         connect(m_processor.data(), &BaseEditorDocumentProcessor::cppDocumentUpdated, this,
                 [this](const CPlusPlus::Document::Ptr document) {
                     // Update syntax highlighter
-                    if (BaseSyntaxHighlighterRunner *highlighter = syntaxHighlighterRunner())
+                    if (SyntaxHighlighterRunner *highlighter = syntaxHighlighterRunner())
                         highlighter->setLanguageFeaturesFlags(document->languageFeatures().flags);
 
                     m_overviewModel.update(usesClangd() ? nullptr : document);
diff --git a/src/plugins/cppeditor/semantichighlighter.cpp b/src/plugins/cppeditor/semantichighlighter.cpp
index 499b1eef6c9..fe52bbdebd4 100644
--- a/src/plugins/cppeditor/semantichighlighter.cpp
+++ b/src/plugins/cppeditor/semantichighlighter.cpp
@@ -112,7 +112,7 @@ void SemanticHighlighter::handleHighlighterResults()
     QElapsedTimer t;
     t.start();
 
-    BaseSyntaxHighlighterRunner *highlighter = m_baseTextDocument->syntaxHighlighterRunner();
+    SyntaxHighlighterRunner *highlighter = m_baseTextDocument->syntaxHighlighterRunner();
     QTC_ASSERT(highlighter, return);
     incrementalApplyExtraAdditionalFormats(highlighter, m_watcher->future(), from, to, m_formatMap);
 
@@ -200,7 +200,7 @@ void SemanticHighlighter::onHighlighterFinished()
     t.start();
 
     if (!m_watcher->isCanceled() && documentRevision() == m_revision) {
-        BaseSyntaxHighlighterRunner *highlighter = m_baseTextDocument->syntaxHighlighterRunner();
+        SyntaxHighlighterRunner *highlighter = m_baseTextDocument->syntaxHighlighterRunner();
         if (QTC_GUARD(highlighter)) {
             qCDebug(log) << "onHighlighterFinished() - clearing formats";
             clearExtraAdditionalFormatsUntilEnd(highlighter, m_watcher->future());
diff --git a/src/plugins/languageclient/semantichighlightsupport.cpp b/src/plugins/languageclient/semantichighlightsupport.cpp
index 119966ac525..b7434de18e0 100644
--- a/src/plugins/languageclient/semantichighlightsupport.cpp
+++ b/src/plugins/languageclient/semantichighlightsupport.cpp
@@ -183,7 +183,7 @@ void SemanticTokenSupport::queueDocumentReload(TextEditor::TextDocument *doc)
 void SemanticTokenSupport::clearHighlight(TextEditor::TextDocument *doc)
 {
     if (m_tokens.contains(doc->filePath())){
-        if (TextEditor::BaseSyntaxHighlighterRunner *highlighter = doc->syntaxHighlighterRunner())
+        if (TextEditor::SyntaxHighlighterRunner *highlighter = doc->syntaxHighlighterRunner())
             highlighter->clearAllExtraFormats();
     }
 }
@@ -413,7 +413,7 @@ void SemanticTokenSupport::highlight(const Utils::FilePath &filePath, bool force
     TextDocument *doc = TextDocument::textDocumentForFilePath(filePath);
     if (!doc || LanguageClientManager::clientForDocument(doc) != m_client)
         return;
-    BaseSyntaxHighlighterRunner *highlighter = doc->syntaxHighlighterRunner();
+    SyntaxHighlighterRunner *highlighter = doc->syntaxHighlighterRunner();
     if (!highlighter)
         return;
     const VersionedTokens versionedTokens = m_tokens.value(filePath);
diff --git a/src/plugins/texteditor/semantichighlighter.cpp b/src/plugins/texteditor/semantichighlighter.cpp
index b4f4245036d..9cee346d8b0 100644
--- a/src/plugins/texteditor/semantichighlighter.cpp
+++ b/src/plugins/texteditor/semantichighlighter.cpp
@@ -75,7 +75,7 @@ const Ranges rangesForResult(
 }
 
 void SemanticHighlighter::incrementalApplyExtraAdditionalFormats(
-    BaseSyntaxHighlighterRunner *highlighter,
+    SyntaxHighlighterRunner *highlighter,
     const QFuture<HighlightingResult> &future,
     int from,
     int to,
@@ -128,7 +128,7 @@ void SemanticHighlighter::incrementalApplyExtraAdditionalFormats(
     highlighter->setExtraFormats(blockNumberMap);
 }
 
-void SemanticHighlighter::setExtraAdditionalFormats(BaseSyntaxHighlighterRunner *highlighter,
+void SemanticHighlighter::setExtraAdditionalFormats(SyntaxHighlighterRunner *highlighter,
                                                     const QList<HighlightingResult> &results,
                                                     const QHash<int, QTextCharFormat> &kindToFormat)
 {
@@ -151,7 +151,7 @@ void SemanticHighlighter::setExtraAdditionalFormats(BaseSyntaxHighlighterRunner
 }
 
 void SemanticHighlighter::clearExtraAdditionalFormatsUntilEnd(
-    BaseSyntaxHighlighterRunner *highlighter, const QFuture<HighlightingResult> &future)
+    SyntaxHighlighterRunner *highlighter, const QFuture<HighlightingResult> &future)
 {
     const QTextDocument * const doc = highlighter->document();
     QTextBlock firstBlockToClear = doc->begin();
diff --git a/src/plugins/texteditor/semantichighlighter.h b/src/plugins/texteditor/semantichighlighter.h
index fa841f5b2c6..ad1d854b834 100644
--- a/src/plugins/texteditor/semantichighlighter.h
+++ b/src/plugins/texteditor/semantichighlighter.h
@@ -21,7 +21,7 @@ QT_END_NAMESPACE
 namespace TextEditor {
 
 class SyntaxHighlighter;
-class BaseSyntaxHighlighterRunner;
+class SyntaxHighlighterRunner;
 
 class TEXTEDITOR_EXPORT HighlightingResult
 {
@@ -74,7 +74,7 @@ using Splitter = std::function<const QList<std::pair<HighlightingResult, QTextBl
 // the (to-1).line result.
 // Requires that results of the Future are ordered by line.
 void TEXTEDITOR_EXPORT
-incrementalApplyExtraAdditionalFormats(BaseSyntaxHighlighterRunner *highlighter,
+incrementalApplyExtraAdditionalFormats(SyntaxHighlighterRunner *highlighter,
                                        const QFuture<HighlightingResult> &future,
                                        int from,
                                        int to,
@@ -85,7 +85,7 @@ incrementalApplyExtraAdditionalFormats(BaseSyntaxHighlighterRunner *highlighter,
 // indicated by Result::kind and kindToFormat to the correct location using
 // SyntaxHighlighter::setExtraFormats. In contrast to
 // incrementalApplyExtraAdditionalFormats the results do not have to be ordered by line.
-void TEXTEDITOR_EXPORT setExtraAdditionalFormats(BaseSyntaxHighlighterRunner *highlighter,
+void TEXTEDITOR_EXPORT setExtraAdditionalFormats(SyntaxHighlighterRunner *highlighter,
                                                  const HighlightingResults &results,
                                                  const QHash<int, QTextCharFormat> &kindToFormat);
 
@@ -93,7 +93,7 @@ void TEXTEDITOR_EXPORT setExtraAdditionalFormats(BaseSyntaxHighlighterRunner *hi
 // until the end of the document.
 // Requires that results of the Future are ordered by line.
 void TEXTEDITOR_EXPORT clearExtraAdditionalFormatsUntilEnd(
-    BaseSyntaxHighlighterRunner *highlighter, const QFuture<HighlightingResult> &future);
+    SyntaxHighlighterRunner *highlighter, const QFuture<HighlightingResult> &future);
 
 } // namespace SemanticHighlighter
 } // namespace TextEditor
diff --git a/src/plugins/texteditor/syntaxhighlighterrunner.cpp b/src/plugins/texteditor/syntaxhighlighterrunner.cpp
index e52fdbbecb8..ed4469eabfb 100644
--- a/src/plugins/texteditor/syntaxhighlighterrunner.cpp
+++ b/src/plugins/texteditor/syntaxhighlighterrunner.cpp
@@ -8,6 +8,7 @@
 #include "texteditorsettings.h"
 #include "highlighter.h"
 
+#include <utils/algorithm.h>
 #include <utils/textutils.h>
 
 #include <QMetaObject>
@@ -21,19 +22,20 @@ class SyntaxHighlighterRunnerPrivate : public QObject
 {
     Q_OBJECT
 public:
-    SyntaxHighlighterRunnerPrivate(BaseSyntaxHighlighterRunner::SyntaxHighLighterCreator creator,
+    SyntaxHighlighterRunnerPrivate(SyntaxHighlighterRunner::SyntaxHighlighterCreator creator,
                                    QTextDocument *document,
+                                   bool async,
                                    FontSettings fontSettings)
-        : m_document(document)
-        , m_fontSettings(fontSettings)
     {
-        if (!m_document) {
+        if (async) {
             m_document = new QTextDocument(this);
             m_document->setDocumentLayout(new TextDocumentLayout(m_document));
+        } else {
+            m_document = document;
         }
 
         m_highlighter.reset(creator());
-        m_highlighter->setFontSettings(m_fontSettings);
+        m_highlighter->setFontSettings(fontSettings);
         m_highlighter->setDocument(m_document);
         m_highlighter->setParent(m_document);
 
@@ -46,7 +48,7 @@ public:
     void changeDocument(int from,
                         int charsRemoved,
                         const QString textAdded,
-                        const QMap<int, BaseSyntaxHighlighterRunner::BlockPreeditData> &blocksPreedit)
+                        const QMap<int, SyntaxHighlighterRunner::BlockPreeditData> &blocksPreedit)
     {
         QTextCursor cursor(m_document);
         cursor.setPosition(qMin(m_document->characterCount() - 1, from + charsRemoved));
@@ -95,48 +97,69 @@ public:
 
     std::unique_ptr<SyntaxHighlighter> m_highlighter;
     QTextDocument *m_document = nullptr;
-    FontSettings m_fontSettings;
 
 signals:
     void resultsReady(const QList<SyntaxHighlighter::Result> &result);
 
 };
 
-// ----------------------------- BaseSyntaxHighlighterRunner --------------------------------------
-
-BaseSyntaxHighlighterRunner::BaseSyntaxHighlighterRunner(
-    BaseSyntaxHighlighterRunner::SyntaxHighLighterCreator creator,
-    QTextDocument *document,
-    const TextEditor::FontSettings &fontSettings)
-    : d(new SyntaxHighlighterRunnerPrivate(creator, document, fontSettings))
+SyntaxHighlighterRunner::SyntaxHighlighterRunner(SyntaxHighlighterCreator creator,
+                                                 QTextDocument *document,
+                                                 bool async,
+                                                 const TextEditor::FontSettings &fontSettings)
+    : d(new SyntaxHighlighterRunnerPrivate(creator, document, async, fontSettings))
     , m_document(document)
 {
     m_useGenericHighlighter = qobject_cast<Highlighter *>(d->m_highlighter.get());
 
-    if (document == nullptr)
-        return;
+    if (async) {
+        m_thread.emplace();
+        d->moveToThread(&*m_thread);
+        connect(&*m_thread, &QThread::finished, d, &QObject::deleteLater);
+        m_thread->start();
 
-    connect(d.get(),
-            &SyntaxHighlighterRunnerPrivate::resultsReady,
-            this,
-            [this](const QList<SyntaxHighlighter::Result> &result) {
-                auto done = std::find_if(result.cbegin(),
-                                         result.cend(),
-                                         [](const SyntaxHighlighter::Result &res) {
-                                             return res.m_state == SyntaxHighlighter::State::Done;
-                                         });
-                if (done != result.cend()) {
-                    m_syntaxInfoUpdated = SyntaxHighlighter::State::Done;
-                    emit highlightingFinished();
-                    return;
-                }
-                m_syntaxInfoUpdated = SyntaxHighlighter::State::InProgress;
-            });
+        connect(d,
+                &SyntaxHighlighterRunnerPrivate::resultsReady,
+                this,
+                &SyntaxHighlighterRunner::applyFormatRanges);
+
+        changeDocument(0, 0, document->characterCount());
+        connect(document,
+                &QTextDocument::contentsChange,
+                this,
+                &SyntaxHighlighterRunner::changeDocument);
+    } else {
+        connect(d,
+                &SyntaxHighlighterRunnerPrivate::resultsReady,
+                this,
+                [this](const QList<SyntaxHighlighter::Result> &result) {
+                    auto done = std::find_if(result.cbegin(),
+                                             result.cend(),
+                                             [](const SyntaxHighlighter::Result &res) {
+                                                 return res.m_state == SyntaxHighlighter::State::Done;
+                                             });
+                    if (done != result.cend()) {
+                        m_syntaxInfoUpdated = SyntaxHighlighter::State::Done;
+                        emit highlightingFinished();
+                        return;
+                    }
+                    m_syntaxInfoUpdated = SyntaxHighlighter::State::InProgress;
+                });
+    }
 }
 
-BaseSyntaxHighlighterRunner::~BaseSyntaxHighlighterRunner() = default;
+SyntaxHighlighterRunner::~SyntaxHighlighterRunner()
+{
+    if (m_thread) {
+        m_thread->requestInterruption();
+        m_thread->quit();
+        m_thread->wait();
+    } else {
+        delete d;
+    }
+}
 
-void BaseSyntaxHighlighterRunner::applyFormatRanges(const QList<SyntaxHighlighter::Result> &results)
+void SyntaxHighlighterRunner::applyFormatRanges(const QList<SyntaxHighlighter::Result> &results)
 {
     if (m_document == nullptr)
         return;
@@ -164,11 +187,11 @@ void BaseSyntaxHighlighterRunner::applyFormatRanges(const QList<SyntaxHighlighte
     }
 }
 
-void BaseSyntaxHighlighterRunner::changeDocument(int from, int charsRemoved, int charsAdded)
+void SyntaxHighlighterRunner::changeDocument(int from, int charsRemoved, int charsAdded)
 {
     QTC_ASSERT(m_document, return);
     m_syntaxInfoUpdated = SyntaxHighlighter::State::InProgress;
-    QMap<int, BaseSyntaxHighlighterRunner::BlockPreeditData> blocksPreedit;
+    QMap<int, SyntaxHighlighterRunner::BlockPreeditData> blocksPreedit;
     QTextBlock block = m_document->findBlock(from);
     const QTextBlock endBlock = m_document->findBlock(from + charsAdded);
     while (block.isValid() && block != endBlock) {
@@ -179,97 +202,64 @@ void BaseSyntaxHighlighterRunner::changeDocument(int from, int charsRemoved, int
         block = block.next();
     }
     const QString text = Utils::Text::textAt(QTextCursor(m_document), from, charsAdded);
-    QMetaObject::invokeMethod(d.get(), [this, from, charsRemoved, text, blocksPreedit] {
+    QMetaObject::invokeMethod(d, [this, from, charsRemoved, text, blocksPreedit] {
         d->changeDocument(from, charsRemoved, text, blocksPreedit);
     });
 }
 
-bool BaseSyntaxHighlighterRunner::useGenericHighlighter() const
+bool SyntaxHighlighterRunner::useGenericHighlighter() const
 {
     return m_useGenericHighlighter;
 }
 
-void BaseSyntaxHighlighterRunner::setExtraFormats(
+void SyntaxHighlighterRunner::setExtraFormats(
     const QMap<int, QList<QTextLayout::FormatRange>> &formatMap)
 {
-    QMetaObject::invokeMethod(d.get(), [this, formatMap] { d->setExtraFormats(formatMap); });
+    QMetaObject::invokeMethod(d, [this, formatMap] { d->setExtraFormats(formatMap); });
 }
 
-void BaseSyntaxHighlighterRunner::clearExtraFormats(const QList<int> &blockNumbers)
+void SyntaxHighlighterRunner::clearExtraFormats(const QList<int> &blockNumbers)
 {
-    QMetaObject::invokeMethod(d.get(), [this, blockNumbers] { d->clearExtraFormats(blockNumbers); });
+    QMetaObject::invokeMethod(d, [this, blockNumbers] { d->clearExtraFormats(blockNumbers); });
 }
 
-void BaseSyntaxHighlighterRunner::clearAllExtraFormats()
+void SyntaxHighlighterRunner::clearAllExtraFormats()
 {
-    QMetaObject::invokeMethod(d.get(), [this] { d->clearAllExtraFormats(); });
+    QMetaObject::invokeMethod(d, [this] { d->clearAllExtraFormats(); });
 }
 
-void BaseSyntaxHighlighterRunner::setFontSettings(const TextEditor::FontSettings &fontSettings)
+void SyntaxHighlighterRunner::setFontSettings(const TextEditor::FontSettings &fontSettings)
 {
-    QMetaObject::invokeMethod(d.get(), [this, fontSettings] { d->setFontSettings(fontSettings); });
+    QMetaObject::invokeMethod(d, [this, fontSettings] { d->setFontSettings(fontSettings); });
 }
 
-void BaseSyntaxHighlighterRunner::setLanguageFeaturesFlags(unsigned int flags)
+void SyntaxHighlighterRunner::setLanguageFeaturesFlags(unsigned int flags)
 {
-    QMetaObject::invokeMethod(d.get(), [this, flags] { d->setLanguageFeaturesFlags(flags); });
+    QMetaObject::invokeMethod(d, [this, flags] { d->setLanguageFeaturesFlags(flags); });
 }
 
-void BaseSyntaxHighlighterRunner::setEnabled(bool enabled)
+void SyntaxHighlighterRunner::setEnabled(bool enabled)
 {
-    QMetaObject::invokeMethod(d.get(), [this, enabled] { d->setEnabled(enabled); });
+    QMetaObject::invokeMethod(d, [this, enabled] { d->setEnabled(enabled); });
 }
 
-void BaseSyntaxHighlighterRunner::rehighlight()
+void SyntaxHighlighterRunner::rehighlight()
 {
-    QMetaObject::invokeMethod(d.get(), [this] { d->rehighlight(); });
+    QMetaObject::invokeMethod(d, [this] { d->rehighlight(); });
 }
 
-QString BaseSyntaxHighlighterRunner::definitionName()
+QString SyntaxHighlighterRunner::definitionName()
 {
     return m_definitionName;
 }
 
-void BaseSyntaxHighlighterRunner::setDefinitionName(const QString &name)
+void SyntaxHighlighterRunner::setDefinitionName(const QString &name)
 {
     if (name.isEmpty())
         return;
 
     m_definitionName = name;
-    QMetaObject::invokeMethod(d.get(), [this, name] { d->setDefinitionName(name); });
-}
-
-// --------------------------- ThreadedSyntaxHighlighterRunner ------------------------------------
-
-ThreadedSyntaxHighlighterRunner::ThreadedSyntaxHighlighterRunner(SyntaxHighLighterCreator creator,
-                                                                 QTextDocument *document)
-    : BaseSyntaxHighlighterRunner(creator, nullptr)
-{
-    QTC_ASSERT(document, return);
-
-    d->moveToThread(&m_thread);
-    connect(&m_thread, &QThread::finished, d.get(), &QObject::deleteLater);
-    m_thread.start();
-
-    m_document = document;
-    connect(d.get(),
-            &SyntaxHighlighterRunnerPrivate::resultsReady,
-            this,
-            &ThreadedSyntaxHighlighterRunner::applyFormatRanges);
-
-    changeDocument(0, 0, document->characterCount());
-    connect(document,
-            &QTextDocument::contentsChange,
-            this,
-            &ThreadedSyntaxHighlighterRunner::changeDocument);
-}
-
-ThreadedSyntaxHighlighterRunner::~ThreadedSyntaxHighlighterRunner()
-{
-    m_thread.requestInterruption();
-    m_thread.quit();
-    m_thread.wait();
-    d.release();
+    QMetaObject::invokeMethod(d, [this, name] { d->setDefinitionName(name); });
 }
 
 } // namespace TextEditor
diff --git a/src/plugins/texteditor/syntaxhighlighterrunner.h b/src/plugins/texteditor/syntaxhighlighterrunner.h
index 555a9a82930..1d16bec9d4a 100644
--- a/src/plugins/texteditor/syntaxhighlighterrunner.h
+++ b/src/plugins/texteditor/syntaxhighlighterrunner.h
@@ -20,21 +20,22 @@ namespace TextEditor {
 
 class SyntaxHighlighterRunnerPrivate;
 
-class TEXTEDITOR_EXPORT BaseSyntaxHighlighterRunner : public QObject
+class TEXTEDITOR_EXPORT SyntaxHighlighterRunner : public QObject
 {
     Q_OBJECT
 public:
-    using SyntaxHighLighterCreator = std::function<SyntaxHighlighter *()>;
+    using SyntaxHighlighterCreator = std::function<SyntaxHighlighter *()>;
     struct BlockPreeditData {
         int position;
         QString text;
     };
 
-    BaseSyntaxHighlighterRunner(SyntaxHighLighterCreator creator,
-                                QTextDocument *document,
-                                const TextEditor::FontSettings &fontSettings
-                                = TextEditorSettings::fontSettings());
-    virtual ~BaseSyntaxHighlighterRunner();
+    SyntaxHighlighterRunner(SyntaxHighlighterCreator creator,
+                            QTextDocument *document,
+                            bool async,
+                            const TextEditor::FontSettings &fontSettings
+                            = TextEditorSettings::fontSettings());
+    virtual ~SyntaxHighlighterRunner();
 
     void setExtraFormats(const QMap<int, QList<QTextLayout::FormatRange>> &formats);
     void clearExtraFormats(const QList<int> &blockNumbers);
@@ -55,28 +56,16 @@ public:
 signals:
     void highlightingFinished();
 
-protected:
-    std::unique_ptr<SyntaxHighlighterRunnerPrivate> d;
-    QPointer<QTextDocument> m_document = nullptr;
+private:
     void applyFormatRanges(const QList<SyntaxHighlighter::Result> &results);
     void changeDocument(int from, int charsRemoved, int charsAdded);
 
+    SyntaxHighlighterRunnerPrivate *d;
+    QPointer<QTextDocument> m_document = nullptr;
     SyntaxHighlighter::State m_syntaxInfoUpdated = SyntaxHighlighter::State::Done;
-
-private:
     bool m_useGenericHighlighter = false;
     QString m_definitionName;
-};
-
-class TEXTEDITOR_EXPORT ThreadedSyntaxHighlighterRunner : public BaseSyntaxHighlighterRunner
-{
-public:
-    ThreadedSyntaxHighlighterRunner(SyntaxHighLighterCreator SyntaxHighLighterCreator,
-                                    QTextDocument *document);
-    ~ThreadedSyntaxHighlighterRunner();
-
-private:
-    QThread m_thread;
+    std::optional<QThread> m_thread;
 };
 
 } // namespace TextEditor
diff --git a/src/plugins/texteditor/textdocument.cpp b/src/plugins/texteditor/textdocument.cpp
index 5ea17e10970..225221c4780 100644
--- a/src/plugins/texteditor/textdocument.cpp
+++ b/src/plugins/texteditor/textdocument.cpp
@@ -101,7 +101,7 @@ public:
     TextMarks m_marksCache; // Marks not owned
     Utils::Guard m_modificationChangedGuard;
 
-    BaseSyntaxHighlighterRunner *m_highlighterRunner = nullptr;
+    SyntaxHighlighterRunner *m_highlighterRunner = nullptr;
 };
 
 MultiTextCursor TextDocumentPrivate::indentOrUnindent(const MultiTextCursor &cursors,
@@ -635,7 +635,7 @@ QTextDocument *TextDocument::document() const
     return &d->m_document;
 }
 
-BaseSyntaxHighlighterRunner *TextDocument::syntaxHighlighterRunner() const
+SyntaxHighlighterRunner *TextDocument::syntaxHighlighterRunner() const
 {
     return d->m_highlighterRunner;
 }
@@ -917,14 +917,11 @@ void TextDocument::resetSyntaxHighlighter(const std::function<SyntaxHighlighter
     if (d->m_highlighterRunner)
         delete d->m_highlighterRunner;
 
-    static const QString value
-        = qtcEnvironmentVariable("QTC_USE_THREADED_HIGHLIGHTER", "TRUE").toUpper();
-    if (threaded && value == QLatin1String("TRUE")) {
-        d->m_highlighterRunner = new ThreadedSyntaxHighlighterRunner(creator, document());
-        return;
-    }
+    static const bool envValue
+        = qtcEnvironmentVariable("QTC_USE_THREADED_HIGHLIGHTER", "TRUE").toUpper()
+          == QLatin1String("TRUE");
 
-    d->m_highlighterRunner = new BaseSyntaxHighlighterRunner(creator, document());
+    d->m_highlighterRunner = new SyntaxHighlighterRunner(creator, document(), threaded && envValue);
 }
 
 void TextDocument::cleanWhitespace(const QTextCursor &cursor)
diff --git a/src/plugins/texteditor/textdocument.h b/src/plugins/texteditor/textdocument.h
index c7fe881d27e..ad3fe262e24 100644
--- a/src/plugins/texteditor/textdocument.h
+++ b/src/plugins/texteditor/textdocument.h
@@ -34,7 +34,7 @@ class FontSettings;
 class IAssistProvider;
 class StorageSettings;
 class SyntaxHighlighter;
-class BaseSyntaxHighlighterRunner;
+class SyntaxHighlighterRunner;
 class TabSettings;
 class TextDocumentPrivate;
 class TextMark;
@@ -128,7 +128,7 @@ public:
 
     using SyntaxHighLighterCreator = std::function<SyntaxHighlighter *()>;
     void resetSyntaxHighlighter(const SyntaxHighLighterCreator &creator, bool threaded = true);
-    BaseSyntaxHighlighterRunner *syntaxHighlighterRunner() const;
+    SyntaxHighlighterRunner *syntaxHighlighterRunner() const;
 
     bool reload(QString *errorString, QTextCodec *codec);
     void cleanWhitespace(const QTextCursor &cursor);
diff --git a/src/plugins/texteditor/texteditor.cpp b/src/plugins/texteditor/texteditor.cpp
index 7d04cb83d4e..bbe3bf64bd1 100644
--- a/src/plugins/texteditor/texteditor.cpp
+++ b/src/plugins/texteditor/texteditor.cpp
@@ -1936,7 +1936,7 @@ void TextEditorWidgetPrivate::foldLicenseHeader()
             QStringList commentMarker;
             QStringList docMarker;
             HighlighterHelper::Definition def;
-            if (BaseSyntaxHighlighterRunner *highlighter = q->textDocument()->syntaxHighlighterRunner())
+            if (SyntaxHighlighterRunner *highlighter = q->textDocument()->syntaxHighlighterRunner())
                 def = HighlighterHelper::definitionForName(highlighter->definitionName());
 
             if (def.isValid()) {
@@ -3743,7 +3743,7 @@ void TextEditorWidgetPrivate::setupFromDefinition(const KSyntaxHighlighting::Def
 
 KSyntaxHighlighting::Definition TextEditorWidgetPrivate::currentDefinition()
 {
-    if (BaseSyntaxHighlighterRunner *highlighter = m_document->syntaxHighlighterRunner())
+    if (SyntaxHighlighterRunner *highlighter = m_document->syntaxHighlighterRunner())
         return HighlighterHelper::definitionForName(highlighter->definitionName());
     return {};
 }
@@ -8132,7 +8132,7 @@ void TextEditorWidget::setDisplaySettings(const DisplaySettings &ds)
     optionFlags.setFlag(QTextOption::AddSpaceForLineAndParagraphSeparators);
     optionFlags.setFlag(QTextOption::ShowTabsAndSpaces, ds.m_visualizeWhitespace);
     if (optionFlags != currentOptionFlags) {
-        if (BaseSyntaxHighlighterRunner *highlighter = textDocument()->syntaxHighlighterRunner())
+        if (SyntaxHighlighterRunner *highlighter = textDocument()->syntaxHighlighterRunner())
             highlighter->rehighlight();
         QTextOption option = document()->defaultTextOption();
         option.setFlags(optionFlags);
diff --git a/src/plugins/vcsbase/vcsbaseeditor.cpp b/src/plugins/vcsbase/vcsbaseeditor.cpp
index 882896bd763..8eeb2c0ac5a 100644
--- a/src/plugins/vcsbase/vcsbaseeditor.cpp
+++ b/src/plugins/vcsbase/vcsbaseeditor.cpp
@@ -1100,7 +1100,7 @@ void VcsBaseEditorWidget::slotActivateAnnotation()
 
     disconnect(this, &QPlainTextEdit::textChanged, this, &VcsBaseEditorWidget::slotActivateAnnotation);
 
-    if (BaseSyntaxHighlighterRunner *ah = textDocument()->syntaxHighlighterRunner()) {
+    if (SyntaxHighlighterRunner *ah = textDocument()->syntaxHighlighterRunner()) {
         ah->rehighlight();
     } else {
         BaseAnnotationHighlighterCreator creator = annotationHighlighterCreator();
diff --git a/tests/auto/texteditor/highlighter/tst_highlighter.cpp b/tests/auto/texteditor/highlighter/tst_highlighter.cpp
index a7ed427f5da..df9af0c40c3 100644
--- a/tests/auto/texteditor/highlighter/tst_highlighter.cpp
+++ b/tests/auto/texteditor/highlighter/tst_highlighter.cpp
@@ -32,7 +32,7 @@ private slots:
 
 private:
     QTextDocument *doc = nullptr;
-    BaseSyntaxHighlighterRunner *highlighterRunner = nullptr;
+    SyntaxHighlighterRunner *highlighterRunner = nullptr;
     FontSettings fontsettings;
     QHash<int, QTextCharFormat> formatHash;
     QTextCharFormat whitespaceFormat;
@@ -59,8 +59,8 @@ Last)";
     doc = new QTextDocument();
     doc->setPlainText(text);
 
-    highlighterRunner = new BaseSyntaxHighlighterRunner(
-        [this] { return new SyntaxHighlighter(doc, fontsettings); }, doc, fontsettings);
+    highlighterRunner = new SyntaxHighlighterRunner(
+        [this] { return new SyntaxHighlighter(doc, fontsettings); }, doc, false, fontsettings);
 }
 
 static const HighlightingResults &highlightingResults()