4 files changed, 17 insertions, 1 deletions
diff --git a/Userland/Applications/Calendar/main.cpp b/Userland/Applications/Calendar/main.cpp
index 54f0e56042..a69474281c 100644
--- a/Userland/Applications/Calendar/main.cpp
+++ b/Userland/Applications/Calendar/main.cpp
@@ -27,6 +27,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto app = TRY(GUI::Application::try_create(arguments));
 
     Config::pledge_domain("Calendar");
+    Config::monitor_domain("Calendar");
 
     TRY(Core::System::pledge("stdio recvfd sendfd rpath"));
     TRY(Core::System::unveil("/etc/timezone", "r"));
diff --git a/Userland/Libraries/LibGUI/Calendar.cpp b/Userland/Libraries/LibGUI/Calendar.cpp
index a9be42687f..7c12e45deb 100644
--- a/Userland/Libraries/LibGUI/Calendar.cpp
+++ b/Userland/Libraries/LibGUI/Calendar.cpp
@@ -754,4 +754,13 @@ size_t Calendar::day_of_week_index(String const& day_name)
     auto const& day_names = AK::long_day_names;
     return AK::find_index(day_names.begin(), day_names.end(), day_name);
 }
+
+void Calendar::config_string_did_change(String const& domain, String const& group, String const& key, String const& value)
+{
+    VERIFY(domain == "Calendar");
+    if (group == "View" && key == "FirstDayOfWeek") {
+        m_first_day_of_week = static_cast<DayOfWeek>(day_of_week_index(value));
+        update_tiles(m_view_year, m_view_month);
+    }
+}
 }
diff --git a/Userland/Libraries/LibGUI/Calendar.h b/Userland/Libraries/LibGUI/Calendar.h
index 79c105d913..56a2c394bf 100644
--- a/Userland/Libraries/LibGUI/Calendar.h
+++ b/Userland/Libraries/LibGUI/Calendar.h
@@ -8,13 +8,16 @@
 #pragma once
 
 #include <AK/String.h>
+#include <LibConfig/Listener.h>
 #include <LibCore/DateTime.h>
 #include <LibGUI/Frame.h>
 #include <LibGUI/Widget.h>
 
 namespace GUI {
 
-class Calendar final : public GUI::Frame {
+class Calendar final
+    : public GUI::Frame
+    , public Config::Listener {
     C_OBJECT(Calendar)
 
 public:
@@ -67,6 +70,8 @@ public:
         m_unadjusted_tile_size.set_height(height);
     }
 
+    virtual void config_string_did_change(String const&, String const&, String const&, String const&) override;
+
     Function<void()> on_tile_click;
     Function<void()> on_tile_doubleclick;
     Function<void()> on_month_click;
diff --git a/Userland/Services/Taskbar/main.cpp b/Userland/Services/Taskbar/main.cpp
index 25b817ccff..6777fda649 100644
--- a/Userland/Services/Taskbar/main.cpp
+++ b/Userland/Services/Taskbar/main.cpp
@@ -50,6 +50,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto app = TRY(GUI::Application::try_create(arguments));
     Config::pledge_domains({ "Taskbar", "Calendar" });
     Config::monitor_domain("Taskbar");
+    Config::monitor_domain("Calendar");
     app->event_loop().register_signal(SIGCHLD, [](int) {
         // Wait all available children
         while (waitpid(-1, nullptr, WNOHANG) > 0)