doc: Configuration of the db.
opt: Optimized the focus handling.
fix: An order of init.
fix: An event bubbling bug.
opt: Optimized the focus handling.
fix: A typo.
add: Help page.
add: Undo & Redo functions.
add: The 'selected' api of the widget.
mov: Refactored some variables and file.
add: Widget 'added' interface.