* Make sure to always send the correct 'item' member in SSE events.
If a change to item A causes visibility changes to item B, we previously
sent an SSE event for B including the new visibility for B, but included
item and state of A. This leads to client confusion, as it'll update its
internal state for the widget belonging to B with the item state of A.
Make sure to always send the item for B and to omit state in that case.
Closes#690
Signed-off-by: Danny Baumann <dannybaumann@web.de>
