diff --git a/scripts/cpp-check.sh b/scripts/cpp-check.sh
index 732cab7d..20de011d 100755
--- a/scripts/cpp-check.sh
+++ b/scripts/cpp-check.sh
@@ -1,3 +1,3 @@
 #!/usr/bin/env bash
 # TODO: add to following flag to the cppcheck: --addon=cert
-cppcheck --enable=all --library=googletest --suppressions-list=suppressions.txt --error-exitcode=1 "$@" -I lib/commonmarker/src/ -I lib/commonmarker/extensions/ ./src ./tst
+cppcheck --enable=all --library=googletest --suppressions-list=suppressions.txt --inline-suppr --check-level=exhaustive --error-exitcode=1 "$@" -I ./src -I lib/commonmarker/src/ -I lib/commonmarker/extensions/ ./src ./tst
diff --git a/src/about-dialog.cc b/src/about-dialog.cc
index 697e0f4b..c8c847a6 100644
--- a/src/about-dialog.cc
+++ b/src/about-dialog.cc
@@ -48,7 +48,7 @@ void About::hide_about(__attribute__((unused)) int response)
 std::string About::get_logo_image()
 {
   // Use data directory first, used when LibreWeb is installed (Linux or Windows)
-  for (std::string data_dir : Glib::get_system_data_dirs())
+  for (const std::string& data_dir : Glib::get_system_data_dirs())
   {
     std::vector<std::string> path_builder{data_dir, "libreweb", "images", "browser_logo_small.png"};
     std::string file_path = Glib::build_path(G_DIR_SEPARATOR_S, path_builder);
diff --git a/src/draw.cc b/src/draw.cc
index c3f18ab4..e15cfa4a 100644
--- a/src/draw.cc
+++ b/src/draw.cc
@@ -136,7 +136,7 @@ void Draw::event_after(GdkEvent* ev)
 
   if (ev->type == GDK_BUTTON_RELEASE)
   {
-    GdkEventButton* event;
+    const GdkEventButton* event;
     event = reinterpret_cast<GdkEventButton*>(ev);
     if (event->button != GDK_BUTTON_PRIMARY)
       return;
@@ -145,7 +145,7 @@ void Draw::event_after(GdkEvent* ev)
   }
   else if (ev->type == GDK_TOUCH_END)
   {
-    GdkEventTouch* event;
+    const GdkEventTouch* event;
     event = reinterpret_cast<GdkEventTouch*>(ev);
     ex = event->x;
     ey = event->y;
@@ -513,7 +513,7 @@ void Draw::select_all()
 /**
  * \brief Return the Texr mark headings for Table of contents
  */
-std::vector<Glib::RefPtr<Gtk::TextMark>> Draw::get_headings()
+const std::vector<Glib::RefPtr<Gtk::TextMark>>& Draw::get_headings() const
 {
   return headings_toc_;
 }
@@ -1606,7 +1606,7 @@ void Draw::change_cursor(int x, int y)
   auto tags = iter.get_tags();
   for (auto const& tag : tags)
   {
-    char* url = static_cast<char*>(tag->get_data("url"));
+    const char* url = static_cast<char*>(tag->get_data("url"));
     if (url != 0 && (strlen(url) > 0))
     {
       // Link
diff --git a/src/draw.h b/src/draw.h
index 12ee21cb..a3b56e1a 100644
--- a/src/draw.h
+++ b/src/draw.h
@@ -53,7 +53,7 @@ class Draw : public Gtk::TextView
   void paste();
   void del();
   void select_all();
-  std::vector<Glib::RefPtr<Gtk::TextMark>> get_headings();
+  const std::vector<Glib::RefPtr<Gtk::TextMark>>& get_headings() const;
 
   // Signals editor calls
   void make_heading(int heading_level);
diff --git a/src/ipfs-daemon.cc b/src/ipfs-daemon.cc
index 0b517a79..31c29e12 100644
--- a/src/ipfs-daemon.cc
+++ b/src/ipfs-daemon.cc
@@ -28,6 +28,7 @@ void IPFSDaemon::spawn()
   // Check for PID under UNIX
   int daemon_pid = IPFSDaemon::get_existing_pid();
   // Is IPFS Daemon already running?
+  // cppcheck-suppress knownConditionTrueFalse
   if (daemon_pid > 0)
   {
     std::cout << "INFO: IPFS Daemon is already running. Do not start another IPFS process." << std::endl;
diff --git a/src/main-window.cc b/src/main-window.cc
index be960ff7..93ed46df 100644
--- a/src/main-window.cc
+++ b/src/main-window.cc
@@ -22,7 +22,7 @@
 #include <whereami.h>
 
 #if defined(__APPLE__)
-static void osx_will_quit_cb(__attribute__((unused)) GtkosxApplication* app, __attribute__((unused)) gpointer data)
+static void osx_will_quit_cb(__attribute__((unused)) const GtkosxApplication* app, __attribute__((unused)) gpointer data)
 {
   gtk_main_quit();
 }
@@ -358,6 +358,7 @@ void MainWindow::update_status_popover_and_icon()
 void MainWindow::load_stored_settings()
 {
   // Set additional schema directory, when browser is not yet installed
+  // cppcheck-suppress knownConditionTrueFalse
   if (!is_installed())
   {
     // Relative to the binary path
@@ -1065,6 +1066,7 @@ void MainWindow::init_mac_os()
     osx_app = reinterpret_cast<GtkosxApplication*>(g_object_new(GTKOSX_TYPE_APPLICATION, NULL));
     // TODO: Should I implement those terminate signals. Since I disabled quartz accelerators
     MainWindow* mainWindow = this;
+    // If needed: reinterpret_cast<void(*)(GtkosxApplication*, gpointer)>(osx_will_quit_cb))
     g_signal_connect(osx_app, "NSApplicationWillTerminate", G_CALLBACK(osx_will_quit_cb), mainWindow);
     // TODO: Open file callback?
     // g_signal_connect (osx_app, "NSApplicationOpenFile", G_CALLBACK (osx_open_file_cb), mainWindow);
@@ -1266,7 +1268,7 @@ void MainWindow::selectAll()
 /**
  * \brief Triggers when the textview widget changes size
  */
-void MainWindow::on_size_alloc(__attribute__((unused)) Gdk::Rectangle& allocation)
+void MainWindow::on_size_alloc(__attribute__((unused)) const Gdk::Rectangle& allocation)
 {
   if (!is_editor_enabled())
     update_margins();
@@ -1810,7 +1812,7 @@ void MainWindow::forward()
 /**
  * \brief Fill-in table of contents and show
  */
-void MainWindow::set_table_of_contents(std::vector<Glib::RefPtr<Gtk::TextMark>> headings)
+void MainWindow::set_table_of_contents(const std::vector<Glib::RefPtr<Gtk::TextMark>>& headings)
 {
   Gtk::TreeRow heading1Row, heading2Row, heading3Row, heading4Row, heading5Row;
   int previousLevel = 1; // Default heading 1
@@ -2083,7 +2085,7 @@ bool MainWindow::is_editor_enabled()
 std::string MainWindow::get_icon_image_from_theme(const std::string& icon_name, const std::string& typeof_icon)
 {
   // Use data directory first, used when LibreWeb is installed (Linux or Windows)
-  for (std::string data_dir : Glib::get_system_data_dirs())
+  for (const std::string& data_dir : Glib::get_system_data_dirs())
   {
     std::vector<std::string> path_builder{data_dir, "libreweb", "images", "icons", current_icon_theme_, typeof_icon, icon_name + ".png"};
     std::string file_path = Glib::build_path(G_DIR_SEPARATOR_S, path_builder);
diff --git a/src/main-window.h b/src/main-window.h
index ee019f73..b9963c70 100644
--- a/src/main-window.h
+++ b/src/main-window.h
@@ -75,7 +75,7 @@ class MainWindow : public Gtk::Window
   void paste();
   void del();
   void selectAll();
-  void on_size_alloc(Gdk::Rectangle& allocation);
+  void on_size_alloc(const Gdk::Rectangle& allocation);
   void on_toc_row_activated(const Gtk::TreeModel::Path& path, Gtk::TreeViewColumn* column);
   void new_doc();
   void open();
@@ -334,7 +334,7 @@ class MainWindow : public Gtk::Window
   void init_signals();
   void init_mac_os();
   bool is_installed();
-  void set_table_of_contents(std::vector<Glib::RefPtr<Gtk::TextMark>> headings);
+  void set_table_of_contents(const std::vector<Glib::RefPtr<Gtk::TextMark>>& headings);
   void enable_edit();
   void disable_edit();
   bool is_editor_enabled();
diff --git a/src/middleware.h b/src/middleware.h
index 21d0fec9..ca2c370a 100644
--- a/src/middleware.h
+++ b/src/middleware.h
@@ -23,7 +23,7 @@ class Middleware : public MiddlewareInterface
 {
 public:
   explicit Middleware(MainWindow& main_window, const std::string& timeout);
-  virtual ~Middleware();
+  virtual ~Middleware() override;
   void do_request(const std::string& path = std::string(),
                   bool is_set_address_bar = true,
                   bool is_history_request = false,
diff --git a/suppressions.txt b/suppressions.txt
index f616c778..8beae967 100644
--- a/suppressions.txt
+++ b/suppressions.txt
@@ -1,4 +1,5 @@
 missingIncludeSystem
-missingInclude:lib/*
+missingInclude
 unusedFunction
 *:lib/commonmarker/*
+checkersReport