Fix crash when removing an item from a custom widget

src/ui/designer/QGCToolWidget.cc

@@ -529,11 +529,20 @@ void QGCToolWidget::addToolWidget(QGCToolWidgetItem* widget)
         ui->hintLabel = NULL;
     }
     connect(widget, SIGNAL(editingFinished()), this, SLOT(storeWidgetsToSettings()));
-    connect(widget, SIGNAL(destroyed()), this, SLOT(storeWidgetsToSettings()));
+    connect(widget, SIGNAL(destroyed()), this, SLOT(widgetRemoved()));
     toolLayout->addWidget(widget);
     toolItemList.append(widget);
 }
 
+void QGCToolWidget::widgetRemoved()
+{
+    //Must static cast and not dynamic cast since the object is in the destructor
+    //and we only want to use it as a pointer value
+    QGCToolWidgetItem *widget = static_cast<QGCToolWidgetItem *>(QObject::sender());
+    toolItemList.removeAll(widget);
+    storeWidgetsToSettings();
+}
+
 void QGCToolWidget::exportWidget()
 {
     const QString widgetFileExtension(".qgw");

src/ui/designer/QGCToolWidget.h

@@ -102,6 +102,7 @@ protected slots:
     void addCommand();
     void addLabel();
     void setTitle();
+    void widgetRemoved();
 
 private:
     /** Do not use this from outside the class to set the object name,