diff --git a/src/plugins/clangtools/clangtidyclazytool.cpp b/src/plugins/clangtools/clangtidyclazytool.cpp
index 233f6d87eba..aa9853825cf 100644
--- a/src/plugins/clangtools/clangtidyclazytool.cpp
+++ b/src/plugins/clangtools/clangtidyclazytool.cpp
@@ -471,6 +471,13 @@ QList<Diagnostic> ClangTidyClazyTool::read(const QString &filePath,
     return readSerializedDiagnostics(filePath, projectRootDir, logFilePath, errorMessage);
 }
 
+void ClangTidyClazyTool::onNewDiagnosticsAvailable(const QList<Diagnostic> &diagnostics)
+{
+    ClangTool::onNewDiagnosticsAvailable(diagnostics);
+    if (!m_diagnosticFilterModel->filterRegExp().pattern().isEmpty())
+        m_diagnosticFilterModel->invalidateFilter();
+}
+
 } // namespace Internal
 } // namespace ClangTools
 
diff --git a/src/plugins/clangtools/clangtidyclazytool.h b/src/plugins/clangtools/clangtidyclazytool.h
index 7cde29f89d7..24aac6673bf 100644
--- a/src/plugins/clangtools/clangtidyclazytool.h
+++ b/src/plugins/clangtools/clangtidyclazytool.h
@@ -58,6 +58,8 @@ public:
                            const QString &logFilePath,
                            QString *errorMessage) const final;
 
+    void onNewDiagnosticsAvailable(const QList<Diagnostic> &diagnostics) override;
+
 private:
     void handleStateUpdate() final;
 
diff --git a/src/plugins/clangtools/clangtool.h b/src/plugins/clangtools/clangtool.h
index de4d08ceb9d..65dde580095 100644
--- a/src/plugins/clangtools/clangtool.h
+++ b/src/plugins/clangtools/clangtool.h
@@ -62,7 +62,7 @@ public:
 
     const QString &name() const;
 
-    void onNewDiagnosticsAvailable(const QList<Diagnostic> &diagnostics);
+    virtual void onNewDiagnosticsAvailable(const QList<Diagnostic> &diagnostics);
 
 signals:
     void finished(bool success); // For testing.
diff --git a/src/plugins/clangtools/clangtoolsdiagnosticmodel.cpp b/src/plugins/clangtools/clangtoolsdiagnosticmodel.cpp
index 00bf9112b95..5b824f22508 100644
--- a/src/plugins/clangtools/clangtoolsdiagnosticmodel.cpp
+++ b/src/plugins/clangtools/clangtoolsdiagnosticmodel.cpp
@@ -584,14 +584,32 @@ void DiagnosticFilterModel::addSuppressedDiagnostic(
     invalidate();
 }
 
+void DiagnosticFilterModel::invalidateFilter()
+{
+    QSortFilterProxyModel::invalidateFilter();
+}
+
 bool DiagnosticFilterModel::filterAcceptsRow(int sourceRow,
         const QModelIndex &sourceParent) const
 {
     auto model = static_cast<ClangToolsDiagnosticModel *>(sourceModel());
-    Utils::TreeItem *item = model->itemForIndex(sourceParent);
+
+    // FilePathItem - hide if no diagnostics match
+    if (!sourceParent.isValid()) {
+        const QModelIndex filePathIndex = model->index(sourceRow, 0);
+        const int rowCount = model->rowCount(filePathIndex);
+        if (rowCount == 0)
+            return true; // Children not yet added.
+        for (int row = 0; row < rowCount; ++row) {
+            if (filterAcceptsRow(row, filePathIndex))
+                return true;
+        }
+        return false;
+    }
 
     // DiagnosticItem
-    if (auto filePathItem = dynamic_cast<FilePathItem *>(item)) {
+    Utils::TreeItem *parentItem = model->itemForIndex(sourceParent);
+    if (auto filePathItem = dynamic_cast<FilePathItem *>(parentItem)) {
         auto diagnosticItem = dynamic_cast<DiagnosticItem *>(filePathItem->childAt(sourceRow));
         QTC_ASSERT(diagnosticItem, return false);
 
@@ -612,7 +630,7 @@ bool DiagnosticFilterModel::filterAcceptsRow(int sourceRow,
         return diag.description.contains(filterRegExp());
     }
 
-    return true;
+    return true; // ExplainingStepItem
 }
 
 bool DiagnosticFilterModel::lessThan(const QModelIndex &l, const QModelIndex &r) const
diff --git a/src/plugins/clangtools/clangtoolsdiagnosticmodel.h b/src/plugins/clangtools/clangtoolsdiagnosticmodel.h
index 8a69e9def76..22d06992018 100644
--- a/src/plugins/clangtools/clangtoolsdiagnosticmodel.h
+++ b/src/plugins/clangtools/clangtoolsdiagnosticmodel.h
@@ -146,6 +146,8 @@ public:
     void addSuppressedDiagnostic(const SuppressedDiagnostic &diag);
     ProjectExplorer::Project *project() const { return m_project; }
 
+    void invalidateFilter();
+
 private:
     bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
     bool lessThan(const QModelIndex &l, const QModelIndex &r) const override;