diff --git a/Userland/Libraries/LibGUI/Window.cpp b/Userland/Libraries/LibGUI/Window.cpp
index cf99a6a9b8..6b27eb2ad8 100644
--- a/Userland/Libraries/LibGUI/Window.cpp
+++ b/Userland/Libraries/LibGUI/Window.cpp
@@ -204,7 +204,7 @@ void Window::set_title(String title)
     m_title_when_windowless = move(title);
     if (!is_visible())
         return;
-    WindowServerConnection::the().set_window_title(m_window_id, m_title_when_windowless);
+    WindowServerConnection::the().async_set_window_title(m_window_id, m_title_when_windowless);
 }
 
 String Window::title() const
@@ -262,7 +262,7 @@ void Window::set_minimum_size(const Gfx::IntSize& size)
     m_minimum_size_when_windowless = size;
 
     if (is_visible())
-        WindowServerConnection::the().set_window_minimum_size(m_window_id, size);
+        WindowServerConnection::the().async_set_window_minimum_size(m_window_id, size);
 }
 
 void Window::center_on_screen()
@@ -695,7 +695,7 @@ void Window::set_has_alpha_channel(bool value)
     m_back_store = nullptr;
     m_front_store = nullptr;
 
-    WindowServerConnection::the().set_window_has_alpha_channel(m_window_id, value);
+    WindowServerConnection::the().async_set_window_has_alpha_channel(m_window_id, value);
     update();
 }
 
@@ -710,7 +710,7 @@ void Window::set_opacity(float opacity)
     m_opacity_when_windowless = opacity;
     if (!is_visible())
         return;
-    WindowServerConnection::the().set_window_opacity(m_window_id, opacity);
+    WindowServerConnection::the().async_set_window_opacity(m_window_id, opacity);
 }
 
 void Window::set_alpha_hit_threshold(float threshold)
@@ -724,7 +724,7 @@ void Window::set_alpha_hit_threshold(float threshold)
     m_alpha_hit_threshold = threshold;
     if (!is_visible())
         return;
-    WindowServerConnection::the().set_window_alpha_hit_threshold(m_window_id, threshold);
+    WindowServerConnection::the().async_set_window_alpha_hit_threshold(m_window_id, threshold);
 }
 
 void Window::set_hovered_widget(Widget* widget)
@@ -829,7 +829,7 @@ void Window::apply_icon()
     if (!is_visible())
         return;
 
-    WindowServerConnection::the().set_window_icon_bitmap(m_window_id, m_icon->to_shareable_bitmap());
+    WindowServerConnection::the().async_set_window_icon_bitmap(m_window_id, m_icon->to_shareable_bitmap());
 }
 
 void Window::start_interactive_resize()
@@ -978,7 +978,7 @@ void Window::set_base_size(const Gfx::IntSize& base_size)
         return;
     m_base_size = base_size;
     if (is_visible())
-        WindowServerConnection::the().set_window_base_size_and_size_increment(m_window_id, m_base_size, m_size_increment);
+        WindowServerConnection::the().async_set_window_base_size_and_size_increment(m_window_id, m_base_size, m_size_increment);
 }
 
 void Window::set_size_increment(const Gfx::IntSize& size_increment)
@@ -987,7 +987,7 @@ void Window::set_size_increment(const Gfx::IntSize& size_increment)
         return;
     m_size_increment = size_increment;
     if (is_visible())
-        WindowServerConnection::the().set_window_base_size_and_size_increment(m_window_id, m_base_size, m_size_increment);
+        WindowServerConnection::the().async_set_window_base_size_and_size_increment(m_window_id, m_base_size, m_size_increment);
 }
 
 void Window::set_resize_aspect_ratio(const Optional<Gfx::IntSize>& ratio)
@@ -997,7 +997,7 @@ void Window::set_resize_aspect_ratio(const Optional<Gfx::IntSize>& ratio)
 
     m_resize_aspect_ratio = ratio;
     if (is_visible())
-        WindowServerConnection::the().set_window_resize_aspect_ratio(m_window_id, m_resize_aspect_ratio);
+        WindowServerConnection::the().async_set_window_resize_aspect_ratio(m_window_id, m_resize_aspect_ratio);
 }
 
 void Window::did_add_widget(Badge<Widget>, Widget&)
@@ -1038,9 +1038,9 @@ void Window::update_cursor()
     m_effective_cursor = new_cursor;
 
     if (m_custom_cursor)
-        WindowServerConnection::the().set_window_custom_cursor(m_window_id, m_custom_cursor->to_shareable_bitmap());
+        WindowServerConnection::the().async_set_window_custom_cursor(m_window_id, m_custom_cursor->to_shareable_bitmap());
     else
-        WindowServerConnection::the().set_window_cursor(m_window_id, (u32)m_effective_cursor);
+        WindowServerConnection::the().async_set_window_cursor(m_window_id, (u32)m_effective_cursor);
 }
 
 void Window::focus_a_widget_if_possible(FocusSource source)
diff --git a/Userland/Services/WindowServer/WindowServer.ipc b/Userland/Services/WindowServer/WindowServer.ipc
index 4a68ed6c71..aa7da699fc 100644
--- a/Userland/Services/WindowServer/WindowServer.ipc
+++ b/Userland/Services/WindowServer/WindowServer.ipc
@@ -51,7 +51,7 @@ endpoint WindowServer
 
     set_window_menubar(i32 window_id, i32 menubar_id) =|
 
-    set_window_title(i32 window_id, [UTF8] String title) => ()
+    set_window_title(i32 window_id, [UTF8] String title) =|
     get_window_title(i32 window_id) => ([UTF8] String title)
 
     set_window_progress(i32 window_id, Optional<i32> progress) =|
@@ -62,7 +62,7 @@ endpoint WindowServer
     set_window_rect(i32 window_id, Gfx::IntRect rect) => (Gfx::IntRect rect)
     get_window_rect(i32 window_id) => (Gfx::IntRect rect)
 
-    set_window_minimum_size(i32 window_id, Gfx::IntSize size) => ()
+    set_window_minimum_size(i32 window_id, Gfx::IntSize size) =|
     get_window_minimum_size(i32 window_id) => (Gfx::IntSize size)
 
     get_applet_rect_on_screen(i32 window_id) => (Gfx::IntRect rect)
@@ -75,13 +75,13 @@ endpoint WindowServer
     did_finish_painting(i32 window_id, Vector<Gfx::IntRect> rects) =|
 
     set_global_cursor_tracking(i32 window_id, bool enabled) => ()
-    set_window_opacity(i32 window_id, float opacity) => ()
+    set_window_opacity(i32 window_id, float opacity) =|
 
-    set_window_alpha_hit_threshold(i32 window_id, float threshold) => ()
+    set_window_alpha_hit_threshold(i32 window_id, float threshold) =|
 
     set_window_backing_store(i32 window_id, i32 bpp, i32 pitch, IPC::File anon_file, i32 serial, bool has_alpha_channel, Gfx::IntSize size, bool flush_immediately) => ()
 
-    set_window_has_alpha_channel(i32 window_id, bool has_alpha_channel) => ()
+    set_window_has_alpha_channel(i32 window_id, bool has_alpha_channel) =|
     move_window_to_front(i32 window_id) => ()
     set_fullscreen(i32 window_id, bool fullscreen) => ()
     set_frameless(i32 window_id, bool frameless) => ()
@@ -94,11 +94,11 @@ endpoint WindowServer
     set_wallpaper_mode(String mode)  => ()
 
     set_resolution(Gfx::IntSize resolution, int scale_factor) => (bool success, Gfx::IntSize resolution, int scale_factor)
-    set_window_icon_bitmap(i32 window_id, Gfx::ShareableBitmap icon) => ()
+    set_window_icon_bitmap(i32 window_id, Gfx::ShareableBitmap icon) =|
 
     get_wallpaper() => (String path)
-    set_window_cursor(i32 window_id, i32 cursor_type) => ()
-    set_window_custom_cursor(i32 window_id, Gfx::ShareableBitmap cursor) => ()
+    set_window_cursor(i32 window_id, i32 cursor_type) =|
+    set_window_custom_cursor(i32 window_id, Gfx::ShareableBitmap cursor) =|
 
     start_drag([UTF8] String text, HashMap<String,ByteBuffer> mime_data, Gfx::ShareableBitmap drag_bitmap) => (bool started)
 
@@ -106,8 +106,8 @@ endpoint WindowServer
     get_system_theme() => ([UTF8] String theme_name)
     refresh_system_theme() =|
 
-    set_window_base_size_and_size_increment(i32 window_id, Gfx::IntSize base_size, Gfx::IntSize size_increment) => ()
-    set_window_resize_aspect_ratio(i32 window_id, Optional<Gfx::IntSize> resize_aspect_ratio) => ()
+    set_window_base_size_and_size_increment(i32 window_id, Gfx::IntSize base_size, Gfx::IntSize size_increment) =|
+    set_window_resize_aspect_ratio(i32 window_id, Optional<Gfx::IntSize> resize_aspect_ratio) =|
 
     enable_display_link() =|
     disable_display_link() =|