add some comments

src/Gui/propertyeditor/PropertyEditor.cpp

@@ -185,6 +185,9 @@ void PropertyEditor::closeEditor (QWidget * editor, QAbstractItemDelegate::EndEd
 
     QTreeView::closeEditor(editor, hint);
 
+    // If after closing the editor this widget is still in editing state
+    // then a new editor must have been created. So, a transaction must be
+    // opened, too.
     if (autoupdate && this->state() == EditingState) {
         App::Document* doc = App::GetApplication().getActiveDocument();
         if (doc) {

src/Gui/propertyeditor/PropertyItemDelegate.cpp

@@ -117,6 +117,7 @@ bool PropertyItemDelegate::editorEvent (QEvent * event, QAbstractItemModel* mode
 void PropertyItemDelegate::editorClosed(QWidget *editor, QAbstractItemDelegate::EndEditHint hint)
 {
     // don't close the editor when pressing Tab or Shift+Tab
+    // https://forum.freecadweb.org/viewtopic.php?f=3&t=34627#p290957
     if (hint != EditNextItem && hint != EditPreviousItem)
         editor->close();
 }