diff --git a/src/Gui/OverlayManager.cpp b/src/Gui/OverlayManager.cpp
index f1de06a8fdc6..ce44ecf61438 100644
--- a/src/Gui/OverlayManager.cpp
+++ b/src/Gui/OverlayManager.cpp
@@ -136,7 +136,7 @@ class OverlayStyleSheet: public ParameterGrp::ObserverType {
 
     ParameterGrp::handle handle;
     QString activeStyleSheet;
-    bool hideTab;
+    bool hideTab = false;
 
 private:
     QString detectOverlayStyleSheetFileName() const {