diff --git a/src/apprt/gtk/App.zig b/src/apprt/gtk/App.zig
index 033f4788c..c6e2b4d08 100644
--- a/src/apprt/gtk/App.zig
+++ b/src/apprt/gtk/App.zig
@@ -972,6 +972,9 @@ fn loadRuntimeCss(
     const headerbar_foreground = config.@"window-titlebar-foreground" orelse config.foreground;
 
     try writer.print(
+        \\window.without-window-decoration-and-with-titlebar {{
+        \\  border-radius: 0 0;
+        \\}}
         \\widget.unfocused-split {{
         \\ opacity: {d:.2};
         \\ background-color: rgb({d},{d},{d});
diff --git a/src/apprt/gtk/Window.zig b/src/apprt/gtk/Window.zig
index c2700f986..6bfcb0750 100644
--- a/src/apprt/gtk/Window.zig
+++ b/src/apprt/gtk/Window.zig
@@ -209,6 +209,11 @@ pub fn init(self: *Window, app: *App) !void {
     // If we are disabling decorations then disable them right away.
     if (!app.config.@"window-decoration") {
         c.gtk_window_set_decorated(gtk_window, 0);
+
+        // Fix any artifacting that may occur in window corners.
+        if (app.config.@"gtk-titlebar") {
+            c.gtk_widget_add_css_class(window, "without-window-decoration-and-with-titlebar");
+        }
     }
 
     // In debug we show a warning and apply the 'devel' class to the window.