diff --git a/src/Mod/Part/Gui/TaskFaceColors.cpp b/src/Mod/Part/Gui/TaskFaceColors.cpp
index 44f6b33c2b..5629beab81 100644
--- a/src/Mod/Part/Gui/TaskFaceColors.cpp
+++ b/src/Mod/Part/Gui/TaskFaceColors.cpp
@@ -293,6 +293,7 @@ FaceColors::~FaceColors()
     Gui::Selection().rmvSelectionGate();
     d->connectDelDoc.disconnect();
     d->connectDelObj.disconnect();
+    d->connectUndoDoc.disconnect();
     delete d;
 }