Wt

Currently, it is possible to query each widget to see whether is has focus (WWidget::hasFocus()).
This can be used to perform render changes on updates, contained to that widget.

When changes in focus occur, this is always sent to the server, so that this state remains consistent.
The WApplication should be able to tell which element is in focus. That way a developer is able to more easily know where users are on the page, or if some widget should be updated in a certain way.