`on_cursor_position_changed` events don't fire on line-select-mode entry

I'm hooking into cursor events and using them to determine what is currently selected, like so:

def update(event):
    if event.selection_state:
        selected_from = min(
            event._Buffer__cursor_position,
            event.selection_state.original_cursor_position,
        )
        selected_to = max(
            event._Buffer__cursor_position,
            event.selection_state.original_cursor_position,
        )
    ...

buffer = Buffer(on_text_changed=update, on_cursor_position_changed=update)

This works well in visual mode but in visual line mode it doesn't capture the selection (because in this mode the selection appears to be decoupled from cursor position).

Is there a good way to get the selection bounds in this case?

Start with the Buffer callbacks shown in the issue, especially on_cursor_position_changed and selection_state, and trace how visual line mode updates selection independently of cursor position. Check the relevant selection and event-handling code for an existing regression test. Done means selection bounds are observable when entering line-select mode without breaking visual mode behavior.