diff --git a/src/plugins/languageclient/languageclientcodeassist.cpp b/src/plugins/languageclient/languageclientcodeassist.cpp
index 4a813889f9b..497d9596b06 100644
--- a/src/plugins/languageclient/languageclientcodeassist.cpp
+++ b/src/plugins/languageclient/languageclientcodeassist.cpp
@@ -372,6 +372,7 @@ void LanguageClientCompletionAssistProcessor::handleCompletionResponse(
     proposal->m_document = m_document;
     proposal->m_pos = m_pos;
     proposal->setFragile(true);
+    proposal->setSupportsPrefix(false);
     setAsyncProposalAvailable(proposal);
     qCDebug(LOGLSPCOMPLETION) << QTime::currentTime() << " : "
                               << items.count() << " completions handled";
diff --git a/src/plugins/texteditor/codeassist/codeassistant.cpp b/src/plugins/texteditor/codeassist/codeassistant.cpp
index 15c7f56cc82..9abbe3a8f19 100644
--- a/src/plugins/texteditor/codeassist/codeassistant.cpp
+++ b/src/plugins/texteditor/codeassist/codeassistant.cpp
@@ -440,7 +440,7 @@ void CodeAssistantPrivate::notifyChange()
         QTC_ASSERT(m_proposal, return);
         if (m_editorWidget->position() < m_proposal->basePosition()) {
             destroyContext();
-        } else if (!m_proposal->isFragile()) {
+        } else if (m_proposal->supportsPrefix()) {
             m_proposalWidget->updateProposal(
                 m_editorWidget->textAt(m_proposal->basePosition(),
                                      m_editorWidget->position() - m_proposal->basePosition()));
diff --git a/src/plugins/texteditor/codeassist/iassistproposal.cpp b/src/plugins/texteditor/codeassist/iassistproposal.cpp
index fcbe2e83862..bfce6360712 100644
--- a/src/plugins/texteditor/codeassist/iassistproposal.cpp
+++ b/src/plugins/texteditor/codeassist/iassistproposal.cpp
@@ -90,6 +90,11 @@ bool IAssistProposal::isFragile() const
     return m_isFragile;
 }
 
+bool IAssistProposal::supportsPrefix() const
+{
+    return m_supportsPrefix;
+}
+
 /*!
     \fn bool TextEditor::IAssistProposal::isCorrective() const
 
@@ -120,6 +125,11 @@ void IAssistProposal::setFragile(bool fragile)
     m_isFragile = fragile;
 }
 
+void IAssistProposal::setSupportsPrefix(bool supportsPrefix)
+{
+    m_supportsPrefix = supportsPrefix;
+}
+
 /*!
     \fn IAssistModel *TextEditor::IAssistProposal::model() const
 
diff --git a/src/plugins/texteditor/codeassist/iassistproposal.h b/src/plugins/texteditor/codeassist/iassistproposal.h
index 0dbf24462fc..e7ac9131965 100644
--- a/src/plugins/texteditor/codeassist/iassistproposal.h
+++ b/src/plugins/texteditor/codeassist/iassistproposal.h
@@ -43,6 +43,7 @@ public:
 
     int basePosition() const;
     bool isFragile() const;
+    bool supportsPrefix() const;
     virtual bool hasItemsToPropose(const QString &, AssistReason) const { return true; }
     virtual bool isCorrective(TextEditorWidget *editorWidget) const;
     virtual void makeCorrection(TextEditorWidget *editorWidget);
@@ -50,9 +51,11 @@ public:
     virtual IAssistProposalWidget *createWidget() const = 0;
 
     void setFragile(bool fragile);
+    void setSupportsPrefix(bool supportsPrefix);
 protected:
     int m_basePosition;
     bool m_isFragile = false;
+    bool m_supportsPrefix = true;
 };
 
 } // TextEditor