Element editor : improve deletion speed

sources/editor/elementscene.cpp

@@ -745,9 +745,19 @@ void ElementScene::addItems(QVector<QGraphicsItem *> items)
  */
 void ElementScene::removeItems(QVector<QGraphicsItem *> items)
 {
+	const int previous_selected_count{selectedItems().size()};
+
+		//block signal to avoid multiple emit of selection changed,
+		//we emit this signal only once at the end of this function.
+	blockSignals(true);
 	for (const auto &item : items) {
 		removeItem(item);
 	}
+	blockSignals(false);
+
+	if (previous_selected_count != selectedItems().size()) {
+		emit selectionChanged();
+	}
 
 	emit partsRemoved();
 }