Qt Quick Designer doesn't show new property in component.

Qt Quick Designer doesn't show new property in component.
After closing and reopen QML file, it can show.

How to reproduce it.

• 2 QML files is required.
  ex. main.qml and MyComponent.qml

1. open main.qml in Qt Quick Designer. And don't close it.
2. open MyComponent.qml in QML Editor and add new property to it.
3. re-open main.qml in Qt Quick Designer.
The added property isn't shown.
4. close main.qml and reopen it in Qt Quick Designer.
It can show new property.