Fixed crash when SessionItem is deleted while widget is hidden

GUI/coregui/Views/CommonWidgets/SessionItemWidget.cpp

@@ -74,8 +74,11 @@ void SessionItemWidget::subscribe()
 
 void SessionItemWidget::unsubscribe()
 {
-    if (m_currentItem)
+    if (m_currentItem) {
         m_currentItem->mapper()->unsubscribe(this);
+        // should keep setOnItemDestroy alive to track item destruction while widget is hidden
+        m_currentItem->mapper()->setOnItemDestroy([this](SessionItem*) { m_currentItem = 0; }, this);
+    }
 
     unsubscribeFromItem();
 

GUI/coregui/Views/JobWidgets/ParameterTuningWidget.h

@@ -58,8 +58,7 @@ public slots:
 protected:
     void resizeEvent(QResizeEvent* event);
     void contextMenuEvent(QContextMenuEvent*);
-    virtual void subscribeToItem();
-    virtual void unsubscribeFromItem();
+    void subscribeToItem();
 
 private slots:
     void onPropertyChanged(const QString& property_name);