diff --git a/tabbox.cpp b/tabbox.cpp
index 6970edf521..b9867f044b 100644
--- a/tabbox.cpp
+++ b/tabbox.cpp
@@ -220,6 +220,7 @@ TabBox::TabBox( Workspace *ws )
     , wspace(ws)
     , display_refcount( 0 )
     {
+    m_isShown = false;
     m_defaultConfig = TabBoxConfig();
     m_defaultConfig.setTabBoxMode( TabBoxConfig::ClientTabBox );
     m_defaultConfig.setClientListMode( TabBoxConfig::CurrentDesktopClientList );
diff --git a/tabbox/tabboxhandler.cpp b/tabbox/tabboxhandler.cpp
index 4e1eca01c0..d9d0c3a4bc 100644
--- a/tabbox/tabboxhandler.cpp
+++ b/tabbox/tabboxhandler.cpp
@@ -91,6 +91,7 @@ class TabBoxHandlerPrivate
 
 TabBoxHandlerPrivate::TabBoxHandlerPrivate()
     {
+    isShown = false;
     config = TabBoxConfig();
     view = new TabBoxView();
     XSetWindowAttributes attr;