diff --git a/src/plugins/coco/cocolanguageclient.cpp b/src/plugins/coco/cocolanguageclient.cpp
index 7829d167c10..beecc803007 100644
--- a/src/plugins/coco/cocolanguageclient.cpp
+++ b/src/plugins/coco/cocolanguageclient.cpp
@@ -59,6 +59,10 @@ CocoLanguageClient::CocoLanguageClient(const FilePath &coco, const FilePath &csm
             &EditorManager::documentClosed,
             this,
             &CocoLanguageClient::handleDocumentClosed);
+    connect(EditorManager::instance(),
+            &EditorManager::editorOpened,
+            this,
+            &CocoLanguageClient::handleEditorOpened);
     for (IDocument *openDocument : DocumentModel::openedDocuments())
         handleDocumentOpened(openDocument);
 
@@ -70,6 +74,15 @@ CocoLanguageClient::CocoLanguageClient(const FilePath &coco, const FilePath &csm
     initClientCapabilities();
 }
 
+CocoLanguageClient::~CocoLanguageClient()
+{
+    const QList<Core::IEditor *> &editors = Core::DocumentModel::editorsForOpenedDocuments();
+    for (Core::IEditor *editor : editors) {
+        if (auto textEditor = qobject_cast<TextEditor::BaseTextEditor *>(editor))
+            textEditor->editorWidget()->removeHoverHandler(hoverHandler());
+    }
+}
+
 BaseClientInterface *CocoLanguageClient::clientInterface(const FilePath &coco,
                                                          const FilePath &csmes)
 {
@@ -207,6 +220,15 @@ DiagnosticManager *CocoLanguageClient::createDiagnosticManager()
     return new CocoDiagnosticManager(this);
 }
 
+void CocoLanguageClient::handleDiagnostics(const PublishDiagnosticsParams &params)
+{
+    using namespace TextEditor;
+    Client::handleDiagnostics(params);
+    TextDocument *document = documentForFilePath(params.uri().toFilePath());
+    for (BaseTextEditor *editor : BaseTextEditor::textEditorsForDocument(document))
+        editor->editorWidget()->addHoverHandler(hoverHandler());
+}
+
 class CocoTextDocumentCapabilities : public TextDocumentClientCapabilities
 {
 public:
@@ -240,4 +262,12 @@ void CocoLanguageClient::handleDocumentClosed(IDocument *document)
         closeDocument(textDocument);
 }
 
+void CocoLanguageClient::handleEditorOpened(IEditor *editor)
+{
+    if (auto textEditor = qobject_cast<TextEditor::BaseTextEditor *>(editor);
+            textEditor && hasDiagnostics(textEditor->textDocument())) {
+        textEditor->editorWidget()->addHoverHandler(hoverHandler());
+    }
+}
+
 } // namespace Coco
diff --git a/src/plugins/coco/cocolanguageclient.h b/src/plugins/coco/cocolanguageclient.h
index 5fa75508d60..84584ab89a1 100644
--- a/src/plugins/coco/cocolanguageclient.h
+++ b/src/plugins/coco/cocolanguageclient.h
@@ -33,18 +33,20 @@ class CocoLanguageClient : public LanguageClient::Client
 {
 public:
     CocoLanguageClient(const Utils::FilePath &coco, const Utils::FilePath &csmes);
+    ~CocoLanguageClient() override;
 
     LanguageClient::BaseClientInterface *clientInterface(const Utils::FilePath &coco,
                                                          const Utils::FilePath &csmes);
 
 protected:
     LanguageClient::DiagnosticManager *createDiagnosticManager() override;
+    void handleDiagnostics(const LanguageServerProtocol::PublishDiagnosticsParams &params) override;
 
 private:
     void initClientCapabilities();
     void handleDocumentOpened(Core::IDocument *document);
     void handleDocumentClosed(Core::IDocument *document);
+    void handleEditorOpened(Core::IEditor *editor);
 };
 
-
 } // namespace Coco
diff --git a/src/plugins/languageclient/client.cpp b/src/plugins/languageclient/client.cpp
index 759243d6b24..4c360a15f70 100644
--- a/src/plugins/languageclient/client.cpp
+++ b/src/plugins/languageclient/client.cpp
@@ -1102,6 +1102,13 @@ bool Client::hasDiagnostic(const LanguageServerProtocol::DocumentUri &uri,
     return false;
 }
 
+bool Client::hasDiagnostics(const TextEditor::TextDocument *document) const
+{
+    if (m_diagnosticManager)
+        return m_diagnosticManager->hasDiagnostics(document);
+    return false;
+}
+
 DiagnosticManager *Client::createDiagnosticManager()
 {
     return new DiagnosticManager(this);
diff --git a/src/plugins/languageclient/client.h b/src/plugins/languageclient/client.h
index 8d8e5059d87..adb16e5d4cc 100644
--- a/src/plugins/languageclient/client.h
+++ b/src/plugins/languageclient/client.h
@@ -189,6 +189,7 @@ public:
         const QTextCursor &cursor) const;
     bool hasDiagnostic(const LanguageServerProtocol::DocumentUri &uri,
                        const LanguageServerProtocol::Diagnostic &diag) const;
+    bool hasDiagnostics(const TextEditor::TextDocument *document) const;
     void setSemanticTokensHandler(const SemanticTokensHandler &handler);
     void setSymbolStringifier(const LanguageServerProtocol::SymbolStringifier &stringifier);
     LanguageServerProtocol::SymbolStringifier symbolStringifier() const;
diff --git a/src/plugins/languageclient/diagnosticmanager.cpp b/src/plugins/languageclient/diagnosticmanager.cpp
index e772baf3f52..b80ea70b95e 100644
--- a/src/plugins/languageclient/diagnosticmanager.cpp
+++ b/src/plugins/languageclient/diagnosticmanager.cpp
@@ -206,4 +206,16 @@ bool DiagnosticManager::hasDiagnostic(const LanguageServerProtocol::DocumentUri
     return it->diagnostics.contains(diag);
 }
 
+bool DiagnosticManager::hasDiagnostics(const TextDocument *doc) const
+{
+    const FilePath docPath = doc->filePath();
+    const auto it = m_diagnostics.find(DocumentUri::fromFilePath(docPath));
+    if (it == m_diagnostics.end())
+        return {};
+    const int revision = m_client->documentVersion(docPath);
+    if (revision != it->version.value_or(revision))
+        return false;
+    return !it->diagnostics.isEmpty();
+}
+
 } // namespace LanguageClient
diff --git a/src/plugins/languageclient/diagnosticmanager.h b/src/plugins/languageclient/diagnosticmanager.h
index 8844eaeb7f8..c4972524c00 100644
--- a/src/plugins/languageclient/diagnosticmanager.h
+++ b/src/plugins/languageclient/diagnosticmanager.h
@@ -69,6 +69,7 @@ public:
     bool hasDiagnostic(const LanguageServerProtocol::DocumentUri &uri,
                        const TextEditor::TextDocument *doc,
                        const LanguageServerProtocol::Diagnostic &diag) const;
+    bool hasDiagnostics(const TextEditor::TextDocument *doc) const;
 
 signals:
     void textMarkCreated(const Utils::FilePath &path);