diff --git a/HellionChat/Plugin.cs b/HellionChat/Plugin.cs
index 4f987ca..df6fe3f 100755
--- a/HellionChat/Plugin.cs
+++ b/HellionChat/Plugin.cs
@@ -345,6 +345,7 @@ public sealed class Plugin : IAsyncDalamudPlugin
                 new SelfTests.ColorEditorBufferStep(this),
                 new SelfTests.ThemePickerCategoryStep(this),
                 new SelfTests.SettingsWindowOpenStep(this),
+                new SelfTests.OnOpenMainUiRoutesMainWindowStep(this),
                 new SelfTests.ConfigMigrationV20Step(this),
                 new SelfTests.HoverSheenAllocStep(this),
                 new SelfTests.HonorificHeaderRenderStep(this),
diff --git a/HellionChat/SelfTests/OnOpenMainUiRoutesMainWindowStep.cs b/HellionChat/SelfTests/OnOpenMainUiRoutesMainWindowStep.cs
new file mode 100644
index 0000000..d17d46a
--- /dev/null
+++ b/HellionChat/SelfTests/OnOpenMainUiRoutesMainWindowStep.cs
@@ -0,0 +1,45 @@
+using Dalamud.Bindings.ImGui;
+using Dalamud.Plugin.SelfTest;
+
+namespace HellionChat.SelfTests;
+
+internal sealed class OnOpenMainUiRoutesMainWindowStep : ISelfTestStep
+{
+    private readonly Plugin _plugin;
+
+    public OnOpenMainUiRoutesMainWindowStep(Plugin plugin)
+    {
+        _plugin = plugin;
+    }
+
+    public string Name => "Hellion Chat - OpenMainUi routes to MainWindow";
+
+    public SelfTestStepResult RunStep()
+    {
+        var settingsBefore = _plugin.SettingsWindow.IsOpen;
+        var mainBefore = _plugin.MainWindow.IsOpen;
+
+        _plugin.MainWindow.Toggle();
+
+        var mainAfter = _plugin.MainWindow.IsOpen;
+        var settingsAfter = _plugin.SettingsWindow.IsOpen;
+
+        // Restore original state.
+        _plugin.MainWindow.Toggle();
+
+        if (mainAfter == mainBefore)
+        {
+            ImGui.Text("MainWindow did not toggle");
+            return SelfTestStepResult.Fail;
+        }
+        if (settingsAfter != settingsBefore)
+        {
+            ImGui.Text("SettingsWindow state changed unexpectedly");
+            return SelfTestStepResult.Fail;
+        }
+
+        return SelfTestStepResult.Pass;
+    }
+
+    public void CleanUp() { }
+}