diff --git a/DarkUI/Docking/DarkDockGroup.cs b/DarkUI/Docking/DarkDockGroup.cs
index 22235ea..1fedf6f 100644
--- a/DarkUI/Docking/DarkDockGroup.cs
+++ b/DarkUI/Docking/DarkDockGroup.cs
@@ -72,6 +72,8 @@ namespace DarkUI.Docking
 
             if (VisibleContent == null)
                 VisibleContent = dockContent;
+            else
+                dockContent.Visible = false;
 
             var menuItem = new ToolStripMenuItem(dockContent.DockText);
             menuItem.Tag = dockContent;
diff --git a/DarkUI/Docking/DarkDockPanel.cs b/DarkUI/Docking/DarkDockPanel.cs
index f2b6744..01a3dd7 100644
--- a/DarkUI/Docking/DarkDockPanel.cs
+++ b/DarkUI/Docking/DarkDockPanel.cs
@@ -32,6 +32,7 @@ namespace DarkUI.Docking
             get { return _activeContent; }
             internal set
             {
+                // Don't let content visibility changes re-trigger event
                 if (_switchingContent)
                     return;