diff --git a/liteidex/src/3rdparty/qtc_texteditor/generichighlighter/highlighter.cpp b/liteidex/src/3rdparty/qtc_texteditor/generichighlighter/highlighter.cpp
index db4a283f1..e2c465a0b 100644
--- a/liteidex/src/3rdparty/qtc_texteditor/generichighlighter/highlighter.cpp
+++ b/liteidex/src/3rdparty/qtc_texteditor/generichighlighter/highlighter.cpp
@@ -352,8 +352,13 @@ void Highlighter::changeContext(const QString &contextName,
 {
     if (contextName.startsWith(kPop)) {
         QStringList list = contextName.split(kHash, qtSkipEmptyParts);
-        for (int i = 0; i < list.size(); ++i)
+        for (int i = 0; i < list.size(); ++i) {
+            // A malformed definition can attempt to pop the base context. Keep it
+            // as the fallback context instead of underflowing the stack.
+            if (m_contexts.size() <= 1)
+                break;
             m_contexts.pop_back();
+        }
 
         if (extractObservableState(currentBlockState()) >= PersistentsStart) {
             // One or more contexts were popped during during a persistent state.