diff --git a/src/Gui/TaskView/TaskView.cpp b/src/Gui/TaskView/TaskView.cpp
index c08addf9c..fabb2f0f9 100644
--- a/src/Gui/TaskView/TaskView.cpp
+++ b/src/Gui/TaskView/TaskView.cpp
@@ -409,6 +409,8 @@ TaskView::~TaskView()
 {
     connectApplicationActiveDocument.disconnect();
     connectApplicationDeleteDocument.disconnect();
+    connectApplicationUndoDocument.disconnect();
+    connectApplicationRedoDocument.disconnect();
     Gui::Selection().Detach(this);
 }
 
diff --git a/src/Mod/PartDesign/Gui/WorkflowManager.cpp b/src/Mod/PartDesign/Gui/WorkflowManager.cpp
index bedbe73f9..5a9a20050 100644
--- a/src/Mod/PartDesign/Gui/WorkflowManager.cpp
+++ b/src/Mod/PartDesign/Gui/WorkflowManager.cpp
@@ -63,9 +63,10 @@ WorkflowManager::WorkflowManager() {
 }
 
 WorkflowManager::~WorkflowManager() {
-    // won't they will be disconnected on destruction?
+    // they won't be automatically disconnected on destruction!
     connectNewDocument.disconnect ();
     connectFinishRestoreDocument.disconnect ();
+    connectDeleteDocument.disconnect ();
 }