| Chage of the state | Description |
| WSEV_INITIALIZE | When the instance is initialized. |
| WSEV_DELETE | When the instance is released. |
| WSEV_ACTIVATE | When the instance is activated. |
| WSEV_VALUE_CH | When the value of the instance changes. |
| WSEV_VISIBLE_CH | When the visiblity of the instance changes. |
| WSEV_PARENT_VISIBLE_CH | When the visiblity of the parent instance changes. |
| WSEV_EXPOSE | When the instance is exposed. |
| WSEV_RESIZE | When the instance is resized. |
| WSEV_SENSITIVE_CH | When the sensibility of the instance changes. |
| WSEV_PARENT_SENSITIVE_CH | When the sensibility of the parent instance changes. |